CPT Code for Temporal Artery Biopsy

Temporal artery biopsy remains the gold standard for diagnosing giant cell arteritis, a condition that demands urgent medical attention. If you are a medical coder, a practice manager, a surgeon, or a patient trying to understand an upcoming procedure, navigating the billing landscape can feel like walking through a maze. The confusion often starts with a simple question: What is the correct CPT code for a temporal artery biopsy?

This guide cuts through the noise. You will discover the precise coding framework, understand the nuances of unilateral versus bilateral procedures, learn about payer-specific rules, and see how clinical documentation directly impacts reimbursement. We base every piece of information on current, realistic coding standards. You will not find speculative or leaked information here, only a reliable, in-depth resource designed to make you confident in your coding choices.

Understanding the Medical Necessity Behind the Code

Before you even touch a claim form, you must grasp the clinical story the code represents. A CPT code is not just a number; it is a translation of a medical service into a standardized language. For a temporal artery biopsy, this language speaks of urgency, precision, and a search for a diagnosis that can save a patient’s vision.

What Is a Temporal Artery Biopsy?

A temporal artery biopsy is a surgical procedure where a physician removes a segment of the temporal artery. This artery runs superficially along the side of the head, just in front of the ear and above the temple. The surgeon sends the excised tissue to a pathology lab, where a pathologist examines it under a microscope for signs of inflammation characteristic of giant cell arteritis, also known as temporal arteritis.

The procedure is often an outpatient surgery. A surgeon typically performs it under local anesthesia. They make a small incision, identify the artery, and carefully isolate a segment. They then ligate or cauterize the ends and close the incision. The length of the arterial segment matters. A longer segment, ideally 3 to 5 centimeters, increases the diagnostic yield because the inflammation in giant cell arteritis often occurs in a “skip lesion” pattern, meaning diseased sections alternate with healthy ones.

Why Accurate Coding Matters More Than You Think

Getting the code right protects everyone involved. For the provider, accurate coding ensures proper reimbursement for the work performed. It also shields the practice from audit risks. Insurance payers watch surgical codes closely. A pattern of incorrectly coding a bilateral procedure when only a unilateral biopsy was performed can trigger a costly audit.

For the patient, correct coding translates to a correct bill. An error can lead to an unexpected denial of coverage or a higher out-of-pocket expense. In the world of high-deductible health plans, a coding mistake that adds hundreds of dollars to a patient’s responsibility is a significant problem. Accurate coding reflects the integrity of the medical record and the trust between a patient and their healthcare team.

The Primary CPT Code for Temporal Artery Biopsy: 37609

Let us get directly to the heart of the matter. The primary Current Procedural Terminology code you will use for a temporal artery biopsy is 37609.

A Detailed Breakdown of CPT 37609

The official descriptor for this code in the CPT manual is straightforward: “Ligation or biopsy, temporal artery.” This single code covers the entire surgical procedure. When you report 37609, you are telling the payer that a surgeon performed a procedure on the temporal artery that involved either a ligation (tying off) or a biopsy (removing a piece for pathological study). In the context of diagnosing giant cell arteritis, the procedure is almost always a biopsy. The code is the same.

CPT 37609 is a surgical code, meaning it has a global surgical period. This is a critical detail. The global surgical package includes the immediate preoperative care, the surgical procedure itself, and typical, uncomplicated postoperative follow-up care. Medicare defines the global period for 37609 as 10 days. Other payers typically follow the same standard. During these 10 days, you cannot separately bill for routine follow-up visits related to the surgery. This includes wound checks and suture removal. Your reimbursement for the procedure already accounts for these services.

The code sits within the Surgery section of the CPT manual, under the subsection for the cardiovascular system, specifically for arteries and veins. This placement highlights the vascular surgical nature of the work, even though the goal is often rheumatologic or pathologic diagnosis.

A Quick Guide to Common Billing Scenarios

Understanding the code’s application in real life clarifies its use. Let’s look at the most frequent scenarios you will encounter.

• Scenario One: A Standard Unilateral Biopsy. A 72-year-old woman presents with a new headache, jaw claudication, and an elevated erythrocyte sedimentation rate. Her ophthalmologist orders a temporal artery biopsy. The surgeon removes a 4 cm segment from the right temple. You report CPT 37609 once.

• Scenario Two: A Bilateral Biopsy. The same patient has no localizing symptoms on one side. The surgeon decides to perform a biopsy on both the right and left temporal arteries during the same operative session to increase diagnostic sensitivity. The surgeon documents two separate incisions, one on each temple. You report CPT 37609 with modifier 50 for a bilateral procedure.

• Scenario Three: Biopsy with Other Procedures. A patient needs a temporal artery biopsy and a separate, unrelated procedure during the same operative session, such as a carpal tunnel release. You report 37609 for the biopsy and the specific code for the carpal tunnel release. You append modifier 59 (Distinct Procedural Service) or XS (Separate Structure) to the carpal tunnel release code to indicate it was a distinct, separate procedure from the biopsy. This prevents the two services from being incorrectly bundled.

Critical Nuances: Unilateral vs. Bilateral Coding

The most significant area for confusion—and the place where most coding errors occur—is the distinction between a unilateral and a bilateral temporal artery biopsy. Getting this wrong is a costly mistake. A payer will reject a bilateral claim if the documentation supports only a unilateral procedure.

When to Use Modifier 50 for Bilateral Surgery

Surgeons often perform bilateral temporal artery biopsies. Studies show that performing biopsies on both sides increases the chance of capturing the telltale inflammation, particularly when skip lesions are present. From a coding perspective, you must clearly communicate that the work happened on both sides of the body.

To indicate a bilateral procedure, you append modifier 50 to the single CPT code 37609. Do not report 37609 on two separate lines with a modifier for left and right, like LT and RT. CPT instruction is explicit for codes designated as “bilateral” in the Medicare Physician Fee Schedule; you should use modifier 50 on a single line. You then adjust your fee. A bilateral procedure typically pays 150% of the unilateral rate. You report the code once on a single line, append modifier 50, and set the charge at 150% of your standard fee for the unilateral service. The payer processes this as a single bilateral procedure.

The documentation must explicitly state that the surgeon performed a biopsy on both the right and left temporal arteries. The operative report should describe two separate incisions, two distinct tissue specimens, and the labeling of each specimen as “right temporal artery” and “left temporal artery.” Without this explicit documentation, you cannot code a bilateral procedure. A single incision that yields a single specimen is a unilateral procedure, even if the surgeon’s intent was to be thorough.

The Dangerous Assumption of Bilateral Surgery

Never assume a bilateral procedure. The default assumption for a temporal artery biopsy must be that it is unilateral unless the operative report proves otherwise. Many surgeons, even when they intend to be thorough, may harvest an adequate length of artery from a single side and stop. The clinical dictum now often favors a long-segment unilateral biopsy over a mandatory bilateral approach unless specific clinical signs point to bilateral disease.

Reviewing the pathology report is a crucial auditing step. If the pathology lab received only a single container labeled “temporal artery,” the procedure was unilateral. If the lab received two containers, one labeled “right temporal artery” and the other “left temporal artery,” you have documentation supporting a bilateral claim. A mismatch between the claim and the pathology report is a red flag for an auditor.

Reporting Unilateral Procedures: Right vs. Left

The designation of which side the surgeon biopsied matters for the patient’s medical record. For a unilateral biopsy, the CPT code itself does not change. You still use 37609. To specify the side, you can append an anatomical modifier.

• Use modifier LT for a left-sided procedure.

• Use modifier RT for a right-sided procedure.

Many payers do not require these anatomical modifiers for processing the claim on a non-paired organ or structure. However, best practice and accurate record-keeping dictate you should use them. These modifiers become invaluable if the patient requires a second biopsy on the other side at a later date. The LT and RT modifiers immediately show the payer that the new procedure is not a duplicate service but a medically necessary operation on a different anatomical site.

Payer-Specific Rules: Navigating Medicare and Commercial Plans

A master coder knows that the CPT code is just the starting point. The final destination of a clean, paid claim depends on navigating the specific rules of each payer. Medicare, the largest payer in the United States, sets many standards, but commercial insurers can and do deviate.

Medicare Billing Guidelines and LCDs

For Medicare, the CPT code 37609 is a covered service when performed for medically necessary reasons. The diagnosis of suspected giant cell arteritis is the primary condition that justifies the procedure. To establish medical necessity, the patient’s chart should document signs, symptoms, and laboratory findings that support the suspicion. These include a new type of headache, scalp tenderness, visual disturbances, jaw pain with chewing (jaw claudication), and elevated inflammatory markers like an erythrocyte sedimentation rate or C-reactive protein.

Medicare Administrative Contractors issue Local Coverage Determinations that can specify the conditions of coverage for a temporal artery biopsy. You must check the LCD for your jurisdiction. While a national coverage determination does not exist for this procedure, a local LCD might specify that a trial of corticosteroid therapy should not delay the biopsy. The reason is clinical: steroid treatment can alter the histological findings and reduce the diagnostic sensitivity of the biopsy. The documentation should show the biopsy was performed promptly, ideally within one to two weeks of starting steroids.

In a Medicare audit, the documentation must demonstrate that the patient’s clinical picture aligned with the American College of Rheumatology’s diagnostic criteria for giant cell arteritis. The link between the clinical presentation and the decision to operate is the story your documentation must tell. A claim for 37609 linked only to a vague diagnosis code like “headache” or “temporal pain” will not pass scrutiny. The diagnosis code for giant cell arteritis, or at least a constellation of symptoms, must anchor the claim.

Commercial Insurance Preauthorization Traps

Commercial payers introduce another layer of complexity. Many require prior authorization for a temporal artery biopsy, classifying it as a non-emergency surgical procedure. You must verify the patient’s benefits and initiate the authorization request well in advance of the scheduled surgery. Failure to secure authorization can result in a denial of the claim, leaving the provider and the patient in a difficult financial position.

When seeking authorization, you provide the CPT code 37609 and the relevant ICD-10-CM diagnosis codes. The clinical documentation you submit with the authorization request should summarize the patient’s symptoms, lab results, and the rationale for the biopsy. A brief, clear letter of medical necessity from the ordering physician is a powerful tool. This letter should explicitly state that a temporal artery biopsy is required to rule out giant cell arteritis and guide life-saving corticosteroid therapy.

Some commercial payers may have a policy that considers a temporal artery biopsy as part of a broader treatment pathway. They might question the need for a bilateral procedure more aggressively than for a unilateral one. Be prepared to provide evidence-based literature supporting the bilateral approach if the surgeon chooses it, specifically citing the issue of skip lesions. The key is proactive communication. Do not give the payer a reason to question the claim after the fact.

ICD-10-CM Diagnosis Code Linkage

The CPT code tells the payer what you did. The ICD-10-CM code tells the payer why you did it. This link is the core of medical necessity. A temporal artery biopsy is a surgical procedure with a specific diagnostic intent, and your diagnosis codes must reflect that intent perfectly.

Primary Diagnoses That Justify Medical Necessity

The most specific and justifiable diagnosis code is for the condition you are trying to find.

• M31.6 is the code for Other giant cell arteritis. This is the most common diagnosis linked to CPT 37609. Even if the final pathology report returns negative, you can still use M31.6 for the biopsy if that was the preoperative working diagnosis. The physician’s suspicion based on the clinical presentation is what drives the medical necessity for the procedure, not the final pathological result. This is a fundamental principle of diagnostic coding.

• M31.5 is the code for Giant cell arteritis with polymyalgia rheumatica. If the patient has symptoms of both conditions, this is the correct code.

• I77.6 is the code for Arteritis, unspecified. Use this sparingly and only when the clinical picture is suggestive of an inflammatory arteritis but does not precisely fit the profile for giant cell arteritis.

Secondary Diagnosis Codes for Complete Documentation

You should also code all the signs and symptoms that contributed to the decision to operate. These secondary codes paint a complete picture of the patient’s clinical severity.

• R51: Headache

• H53.8: Other visual disturbances (such as transient vision loss, diplopia)

• M79.1: Myalgia (for patients with muscle pain from polymyalgia rheumatica)

• R50.9: Fever, unspecified

• R53.81: Other malaise

• R79.1: Elevated C-reactive protein

The sequence is important. Always list the suspected definitive diagnosis first, such as M31.6, followed by the significant signs and symptoms. This tells the payer: “I suspected giant cell arteritis, which is why I performed the biopsy, and the patient was suffering from these specific symptoms.” This coding practice creates a defensible, transparent narrative that protects you in the event of an audit.

A Realistic Walkthrough of the Procedure and Its Documentation

To truly master the coding, you must visualize the operating room and the surgeon’s dictation. The documentation is the source of truth. A coder’s job is to extract the coded story from the physician’s notes without fabricating any part of it.

Inside the Operating Room: What the Surgeon Documents

The surgeon will dictate an operative report. This is the single most important document for coding. The report should detail the procedure in a clear, chronological narrative. You will look for several key components to substantiate a code for a temporal artery biopsy.

First, the surgeon documents the patient’s identity and the preoperative diagnosis. This diagnosis should match the rationale for the surgery and align with your ICD-10 code choice. The surgeon then describes the anesthesia. For a temporal artery biopsy, this is typically a local anesthetic, sometimes with monitored anesthesia care.

The detailed surgical procedure note begins with the location. The surgeon specifies “right temporal region” or “left temporal region.” They describe the preparation and draping of the surgical site in a sterile fashion. They then detail the incision. A skilled surgeon will describe the incision’s relationship to the palpable artery and the hairline, often a vertical or slightly curved incision made directly over the pulse.

The next step is the critical dissection. The surgeon identifies and protects the temporal branch of the facial nerve, a key step to avoid nerve damage. They carefully dissect the surrounding tissue to isolate the temporal artery. They then ligate the distal and proximal ends of the intended specimen segment with fine sutures or clips. The surgeon excises the intervening segment of the artery. The documentation should state the length of the excised segment, often “a 4.0 cm segment of the right temporal artery was excised.”

The surgeon then achieves hemostasis, ensuring no active bleeding from the cut ends. They close the incision in layers, usually with absorbable sutures for the deep dermal layer and a non-absorbable or subcuticular suture for the skin. A sterile dressing is applied. The surgeon dictates the patient’s condition upon leaving the operating room and states that all sponge and needle counts were correct.

If a bilateral procedure occurs, the surgeon dictates this entire sequence twice, clearly labeling the first side and the second side. The report will state that a separate incision was made on the opposite temple, and a second specimen was excised and labeled distinctly.

The Pathology Report as a Coding Validation Tool

The pathology report is a secondary but vital source of information. While you do not code the CPT procedure from the pathology report, the report provides a valuable audit trail that validates your coding choices.

The pathology report will list the specimen source exactly as it was labeled in the operating room. A valid unilateral procedure will have one specimen source labeled “Temporal artery, right” or similar. A bilateral procedure must have two separate entries, for example:

1. “Temporal artery, right”

2. “Temporal artery, left”

If your claim reports a bilateral procedure with modifier 50 but the pathology report lists only a single specimen, you have a documentation discrepancy that must be resolved before the claim can be considered clean. The report also gives the specimen measurements, which should match the surgeon’s measurements. Finally, the microscopic diagnosis confirms the presence or absence of arteritis, completing the clinical story.

The Global Surgical Package: Understanding the 10-Day Clock

Reporting CPT 37609 triggers the rules of the global surgical package. Ignoring these rules leads to unbundling errors and claim denials. You must treat the period immediately after the surgery as a single, bundled payment for a package of services.

What Services Are Bundled Into CPT 37609

The global surgical package concept means you should not nickle-and-dime a payer for services that are a standard part of the biopsy. For a major surgery, the global period is 90 days. For a minor procedure like a temporal artery biopsy, Medicare and most payers assign a 10-day global period. The following services are part of the 10-day global package for 37609 and are not separately billable:

• Preoperative Visit: The evaluation the day of or the day before the procedure where the surgeon decides to operate and the patient consents.

• Local Anesthesia: The infiltration of lidocaine or another local anesthetic is part of the surgical procedure.

• The Operation Itself: All technical aspects of isolating, ligating, and removing the artery segment, and closing the wound.

• Typical Postoperative Care: This includes all routine follow-up visits related to the surgery for 10 days. A visit for a simple wound check, dressing change, or to ensure there is no hematoma is included. Even suture removal, which typically happens 7-10 days post-op, is included in the global payment.

Services You Can Bill Separately

You can bill separately for services that are distinct and not a typical part of the post-operative care.

• Diagnostic Tests: The surgeon may order a preoperative lab test. You can bill for the lab’s service.

• Pathology Service: The surgeon sends the specimen to a pathologist. The pathologist or pathology lab bills separately for the professional and technical components of examining the tissue (CPT codes 88305 for the biopsy examination, potentially with additional special stains).

• Managing Unrelated Conditions: If the patient has a separate, pre-existing condition like diabetes, and the surgeon actively manages that condition during the global period, you can bill for the separate evaluation and management service with modifier 24.

• Treating a Complication: If the patient returns to the operating room for a post-operative hematoma evacuation, that is a separate, billable procedure with modifier 78.

Advanced Coding Scenarios: Modifiers and Multiple Procedures

Real-world surgery is not always clean and simple. A patient might need more than just a biopsy. Applying the correct modifiers in these complex scenarios is the mark of a true coding professional.

Using Modifier 59/XS for Distinct Procedures

A common scenario is a temporal artery biopsy performed during the same operative session as another distinct surgical procedure. For example, an ophthalmologist might perform a temporal artery biopsy and an unrelated eyelid surgery. Or a general surgeon might perform the biopsy and an unrelated skin lesion excision on the neck.

Because the National Correct Coding Initiative bundles many procedure combinations, you need a modifier to override the edit and show the procedures were separate and distinct. The most recognized modifier for this is the X{EPSU} modifiers, primarily XS (Separate Structure). The temporal artery and a lesion on an eyelid or neck are clearly separate anatomical structures. You append the XS modifier to the secondary, lesser-valued procedure code.

The classic modifier 59 (Distinct Procedural Service) also works but is more general. Payers increasingly prefer the more specific X modifiers. Your claim would look like this:

• Line 1: 37609 (Temporal artery biopsy)

• Line 2: 11442-59 or 11442-XS (Excision of a benign lesion on the neck)

Your documentation must support the distinct nature of the services. The operative report should detail the separate prepping, draping, incision, and closure of each site. A claim like this without documentation will be denied on post-payment review.

The Role of Modifier 51 vs. 50: A Critical Distinction

A common point of confusion for new coders is the difference between modifier 51 and modifier 50 when dealing with bilateral procedures.

• Modifier 50 is for a bilateral procedure. You use it when a single code is performed on both sides of the body during the same session. For a bilateral temporal artery biopsy, 37609-50 is the correct claim. The procedure is inherently a bilateral surgery described by one code.

• Modifier 51 is for multiple procedures. You use it when a surgeon performs different, distinct procedures in the same session. If a surgeon performs a right temporal artery biopsy and a left carpal tunnel release, you would use modifier 51 (or more commonly, follow payer rules where the highest-valued procedure is listed first, and the subsequent procedures are reduced automatically without the modifier).

You should never append modifier 51 to the second side of a bilateral procedure. A bilateral temporal artery biopsy is not a multiple procedure scenario; it is a bilateral procedure scenario. Appending 37609-50-51 is incorrect and will cause your claim to be rejected. The correct logic is to submit a single line item with the 50 modifier.

Turning a Claim Into a Paid Check: A Step-by-Step Billing Checklist

Now you can translate this knowledge into a practical, systematic workflow. When you sit down to code a claim for a temporal artery biopsy, follow this checklist to ensure accuracy.

1. Locate the Operative Report. Read it in its entirety. Identify the procedure performed. Is it a ligation or a biopsy? Confirm the laterality. Is it right, left, or bilateral? Document the date of service.

2. Select the Primary CPT Code. Enter 37609 as the primary surgical service.

3. Determine the Correct Modifiers. Based on your operative report analysis, decide on the required modifiers.

   • Bilateral? Append modifier 50.

   • Unilateral Right? Append modifier RT.

   • Unilateral Left? Append modifier LT.

   • A distinct, separate procedure also performed? Append modifier XS to the separate procedure.

4. Link the ICD-10-CM Diagnoses. Assign the primary code that represents the preoperative indication, such as M31.6. Link any relevant secondary signs and symptoms codes in descending order of importance. Ensure you have a maximum of four codes linked to the 37609 line item on the claim form.

5. Verify the Global Period. Recognize that the date of service starts a 10-day global period. Check the patient’s schedule to ensure no unbundled postoperative visits are scheduled within that window.

6. Check for Prior Authorization. Confirm that any required authorization was obtained and the authorization number is linked to the claim.

7. Audit Against the Pathology Report. Once the pathology results are final, do a quick reconciliation. Does the number of specimens in the report match the number of procedures you billed? This is your final, definitive quality check before submitting the claim.

Fair Reimbursement: Understanding the Value of Your Work

Knowing the code is one thing; understanding its value is another. Reimbursement for CPT 37609 reflects the surgical skill, the clinical knowledge, and the resources required to perform the procedure safely.

Medicare Physician Fee Schedule for 37609

The Medicare Physician Fee Schedule provides a public benchmark for the value of a medical service. The schedule assigns a relative value unit to each code, which, when multiplied by the annual conversion factor, produces a dollar amount. The values vary slightly by geographic location due to geographic practice cost indices.

To give you a realistic, non-binding estimate of the national payment, a unilateral temporal artery biopsy (37609) in a facility setting typically reimburses around $300 to $400. A bilateral biopsy (37609-50) pays 150% of this amount, so roughly $450 to $600. These figures represent the surgeon’s professional fee only. The facility bills separately for the operating room, supplies, and drugs. The pathologist bills separately for interpreting the tissue specimen.

These amounts illustrate why accurate coding is essential. An incorrectly coded unilateral procedure as bilateral artificially inflates the reimbursement by 50% and exposes the practice to charges of false claims. The reward is not worth the risk. Precise, honest coding ensures you receive every dollar you fairly earn.

Pricing Your Bilateral Claim Correctly

When submitting a claim for a bilateral procedure with modifier 50, you must not simply double your unilateral charge. The standard payer logic applies a multiple surgery reduction rule to the second side. The formula is 100% for the first side and 50% for the second side, yielding a total payment of 150% of the fee schedule rate.

Therefore, your charge should reflect this logic. If your standard fee for 37609 is $1,000.00, your charge for 37609-50 should be $1,500.00. Submitting a charge of $2,000.00 for a bilateral procedure—simply doubling your fee—is incorrect. The payer will automatically reduce it to the allowed amount, which will be 150% of the allowed amount for a unilateral procedure. Your consistent adherence to this pricing rule shows a mature, compliant billing operation.

Mastering Diagnostic Accuracy: Clinical Pathways and Diagnostic Tests

A deep understanding of the clinical pathway that leads a patient to a temporal artery biopsy enhances your ability to code correctly. You transition from a data entry clerk to a medical professional who understands the story behind the numbers.

The Role of Lab Work and Imaging

Before a surgeon picks up a scalpel, other physicians have gathered a wealth of data. The referring physician, often a primary care doctor, a rheumatologist, or an ophthalmologist, sends a patient for a biopsy based on a compelling clinical picture. This picture is built with specific tests.

The cornerstone lab tests are the erythrocyte sedimentation rate and the C-reactive protein. These are nonspecific markers of inflammation, but in a patient with classic symptoms, a markedly elevated ESR is almost a prerequisite for considering giant cell arteritis. A normal ESR makes the diagnosis far less likely but does not rule it out. The clinical suspicion, combined with the lab values, creates the medical necessity for the procedure.

Color duplex ultrasonography of the temporal arteries is an emerging, non-invasive imaging technique. In skilled hands, a “halo sign”—a dark, hypoechoic circumferential wall thickening around the artery lumen—is highly specific for active vasculitis. Some European centers now use ultrasound as a first-line diagnostic tool, potentially foregoing a biopsy in clear-cut cases. However, in the United States, while ultrasound can help locate the optimal site for biopsy or support the diagnosis, the biopsy remains the definitive gold standard for starting life-altering, long-term corticosteroid therapy. The clinical note often includes ultrasound findings to bolster the argument for proceeding with the surgical biopsy.

Biopsy Results: Positive vs. Negative and What Comes Next

Your coding does not change based on the outcome of the biopsy. The medical necessity was established before the surgery. A final pathological diagnosis of “negative for arteritis” does not mean you should change the primary linked diagnosis from M31.6 to a symptom code. The physician’s working diagnosis was M31.6, and that is what drove the decision to operate.

For the patient, a positive biopsy means a definitive diagnosis of giant cell arteritis. The physician will likely start a high-dose corticosteroid regimen immediately to prevent vision loss and taper it slowly over many months. A negative biopsy does not entirely rule out the disease, especially if the clinical suspicion is overwhelmingly high and the excised segment was short. The clinician must make a judgment call. Some patients with a negative biopsy are still treated for presumed giant cell arteritis if the clinical picture is strong enough. This situation highlights the diagnostic challenge and the reason why a clinical diagnosis is sometimes accepted.

Coding from the Pathologist’s Perspective

While the CPT code 37609 is a surgical code, the pathological examination of the tissue is a separate, billable event. This part of the service is coded by the pathology department.

CPT Code 88307 for Temporal Artery Pathology

The pathologist receives the formalin-fixed temporal artery specimen. They examine it grossly, measuring it, inking the margins, and serially cross-sectioning the entire segment to look for skip lesions. The tissue is then processed, cut into microscopic slides, stained, and examined under a microscope.

The CPT code for the technical and professional work of examining a temporal artery biopsy is 88307. This is a surgical pathology code that represents a Level V examination. The code requires a description of the gross and microscopic examination and a written diagnostic interpretation. It reflects the complexity of the exam, as the pathologist must meticulously scan multiple levels of the artery wall for the presence of lymphocytes, macrophages, multinucleated giant cells, and disruption of the internal elastic lamina. The pathologist may also order special stains, such as an elastic stain or a CD68 immunostain to highlight macrophages, which have their own separate CPT codes. The surgical and pathology coding streams run in parallel, both essential for a complete patient record.

Quiz Yourself: Test Your Coding Knowledge

Solidify your understanding with a quick self-assessment. Read the scenario and choose the best answer.

Scenario: An 82-year-old patient is taken to the operating room. The surgeon documents a preoperative diagnosis of “suspected giant cell arteritis, bilateral.” The surgeon makes an incision on the right temple, isolates and excises a 3.5 cm segment of the right temporal artery, and closes the wound. The surgeon then repeats the entire process on the left temple, excising a 4.0 cm segment of the left temporal artery. The pathology lab receives two separate, labeled containers. What is the single, correct CPT code and modifier combination for the surgeon’s professional services?

1. 37609-LT, 37609-RT-51

2. 37609-50

3. 37609-50, 37609-51

4. 37609

*The correct answer is Option B: 37609-50. You report a single line with modifier 50 to indicate a bilateral surgical procedure. Option A is incorrect because you should not unbundle a bilateral procedure into two unilateral lines with lateral modifiers. Option C is incorrect because modifier 51 is for distinct procedures, not bilateral surgery. Option D is incorrect because it would only represent a unilateral procedure.*

Frequently Asked Questions

We have compiled answers to the most common questions that come from our reader community and our own consulting experience.

What is the CPT code for a temporal artery biopsy?

The CPT code is 37609. Its official descriptor is “Ligation or biopsy, temporal artery.”

Can I code 37609 twice for a bilateral biopsy?

No. You should not report 37609 on two lines. The correct way is to report 37609-50 on a single claim line, with the modifier 50 indicating the procedure was performed bilaterally. Adjust your fee to 150% of your standard unilateral charge.

What ICD-10 code should I link to 37609?

The primary diagnosis code is typically M31.6 (Other giant cell arteritis). Link this code to represent the suspected condition that created the medical necessity for the procedure.

Does a negative biopsy result change the diagnosis code?

No. Medical necessity is based on the preoperative diagnosis. If the physician suspected giant cell arteritis before the surgery, M31.6 remains the primary diagnosis code, even if the pathology report is negative.

Is a temporal artery biopsy always a unilateral procedure?

No. A surgeon may perform a unilateral or a bilateral procedure. The operative report and pathology specimen labeling determine which one was performed. You must never assume a procedure was bilateral; the documentation must explicitly prove it.

What is the global period for CPT 37609?

The global surgical period is 10 days. This means all routine preoperative and postoperative care related to the biopsy is bundled into the payment for the procedure and is not separately billable.

Can I bill for suture removal after a temporal artery biopsy?

No. Suture removal is a standard postoperative service included in the 10-day global surgical package. You cannot submit a separate evaluation and management code for this visit.

What is the pathology code for a temporal artery biopsy?

The pathology examination of the excised tissue is coded with 88307 (Surgical pathology, gross and microscopic examination, Level V). This is billed by the pathologist or the laboratory.

Conclusion

This comprehensive guide has provided a deep and reliable resource for coding a temporal artery biopsy. We established that CPT 37609 is the single, specific code for this procedure, and we clarified the critical distinction between unilateral and bilateral coding using modifier 50. The core lesson is that accurate, defensible coding is entirely dependent on the surgeon’s detailed documentation of the laterality of the procedure. By linking this to a clear preoperative diagnosis like M31.6 and respecting the 10-day global surgical package, you can ensure your practice receives fair reimbursement while maintaining impeccable compliance.

Additional Resources

For continued education and the most current coding news, we recommend the official website of the American Medical Association, where you can find the CPT coding system and latest updates.

• American Medical Association – CPT® (Current Procedural Terminology)