CPT code 84550 – Uric acid blood test

Key takeaways

CPT code 84550 bills a quantitative uric acid test on blood, separate from urine uric acid (84560) and from every metabolic panel.

Medical necessity needs a linked ICD-10 code, and gout (M10.x), hyperuricemia (E79.0) and CKD (N18.x) are the strongest pairings.

Medicare pays 84550 under the Clinical Laboratory Fee Schedule at one national rate of about $4.50, with no MAC-region adjustment.

Missing or non-covered ICD-10 codes cause most denials, and modifier 91 applies only to a clinically distinct same-day repeat.

CPT code 84550: Official descriptor and code placement

CPT code 84550 is officially described as “Uric acid; blood” in the AMA CPT code set. The semicolon is standard CPT shorthand that separates this blood code from its other-source sibling, 84560.

It sits in the 82009-84999 range of the Chemistry subsection, within Pathology and Laboratory. Medicare pays it under the Clinical Laboratory Fee Schedule (CLFS), not the Physician Fee Schedule.

The analyte is uric acid, the end product of purine metabolism. High serum levels drive monosodium urate crystal deposits in joints and soft tissue, which is the mechanism behind gout. Low levels matter in some metabolic conditions.

The test must run in a CLIA-certified lab. When a practice sends the specimen to a reference lab such as Quest Diagnostics, the lab usually bills 84550. The practice bills only the blood draw.

What CPT 84550 covers and what it does not

CPT code 84550 covers a single quantitative measurement of uric acid in blood, usually serum or plasma from a venipuncture. Whole-blood point-of-care testing also bills as 84550. On a CLIA-waived device, Medicare expects modifier QW. Commercial payer rules vary, so confirm them before billing.

Three situations fall outside 84550’s scope and cause billing errors when misapplied.

• Urine uric acid: Urine specimens, including 24-hour collections, bill under 84560 (uric acid; other source). Billing 84550 for a urine sample triggers a denial because the descriptor specifies blood.
• Panel bundling: Uric acid is not a component of the comprehensive metabolic panel (80053) or the basic metabolic panel (80048). It is always billed separately when ordered alongside either panel.
• Synovial fluid analysis: A uric acid level on joint fluid aspirated during a gout workup is an other-source test under 84560. Crystal identification on the same fluid has its own code, 89060.

Clinical indications and medical necessity for CPT 84550

Payers require a documented clinical reason for every uric acid blood test before approving the claim. Adding the test to a routine metabolic panel without a supporting diagnosis is one of the fastest routes to denial.

According to AAPC coding guidance, medical necessity must be established before the specimen is collected, not constructed after the order.

Accepted clinical indications for 84550 include the scenarios below. Recording at least one of them in the chart before the order is placed is the most effective way to prevent denials. Document the specific indication in the same encounter note that generates the lab order.

• Acute or chronic gout: Diagnosing new-onset gout, confirming elevated serum uric acid during an acute attack, or monitoring between attacks to guide urate-lowering therapy.
• Hyperuricemia monitoring: Asymptomatic hyperuricemia identified incidentally or as part of a metabolic workup, particularly when a treatment decision is pending.
• Urate-lowering therapy management: Patients on allopurinol or febuxostat require periodic uric acid measurements to verify the treat-to-target level (typically below 6 mg/dL).
• Chronic kidney disease (CKD): Uric acid elevates with declining renal function; CKD staging workups commonly include 84550 as part of the metabolic profile.
• Metabolic syndrome and cardiovascular risk: Some payers cover uric acid as part of a documented metabolic syndrome evaluation. LCD coverage for this indication varies by MAC region.

ICD-10 codes to pair with CPT code 84550

Selecting the right ICD-10 code is the most important step in submitting a clean 84550 claim. Payers validate the diagnosis against their local coverage determination (LCD) before processing the claim. Using a code that falls outside the covered list, even when the clinical reasoning is sound, results in an automatic denial.

The table below lists the most commonly accepted codes, and the CrossCoder crosswalk tool is useful for confirming current payer-specific coverage pairings.

Always confirm active code status for the current ICD-10-CM edition. Use a site-specific M10.0x code when the chart documents the joint involved. M10.9 is a valid fallback, but a specific code holds up better in an audit.

How the uric acid blood test is performed and documented

CPT code 84550 covers the analysis, not the specimen collection. The two are billed as separate services, and the superbill should capture both when the practice performs the blood draw.

1. Specimen collection: A blood draw (venipuncture) is performed, typically from an antecubital vein. The collection is billed separately under CPT 36415. Serum separator tubes (SST) or lithium heparin plasma tubes are the standard specimen types.
2. Specimen processing and transport: Samples sent to a reference laboratory should be transported at refrigerated temperatures to maintain analyte stability. The lab requisition must include the ordering provider’s NPI and the diagnosis code(s) supporting medical necessity.
3. CLIA-certified analysis: Reference labs typically run a quantitative uricase-based or colorimetric assay, which needs at least a moderate-complexity CLIA certificate. A certificate of waiver covers 84550 only on an FDA-waived point-of-care device, billed with modifier QW.
4. Result reporting: Normal reference range for adults is approximately 2.4-6.0 mg/dL for women and 3.4-7.0 mg/dL for men, though lab-specific reference intervals apply. The result and clinical interpretation should be documented in the patient record before the encounter is closed.
5. Chart documentation for billing: The encounter note must include the clinical indication, the order for the uric acid test, and a reference to the result. Payers can request documentation on post-payment audit. A result without a clear ordering rationale is hard to defend.

Codes confused with or billed alongside CPT 84550

Several coding decisions around 84550 trip up billers consistently. Knowing which codes bill separately, which are bundled, and when modifiers apply prevents both undercoding and compliance exposure. The electronic claim must carry every code and modifier accurately, or it rejects before adjudication.

Modifier 91 is specifically misapplied on 84550 claims. It is valid only when a second uric acid measurement is medically necessary on the same calendar day. That means a change in clinical status, such as a repeat draw after acute treatment. Using it to rebill a failed specimen or a quality-control re-run is incorrect and constitutes a billing error.

Medicare and payer reimbursement rates for CPT code 84550

CPT code 84550 is paid under the Medicare Clinical Laboratory Fee Schedule (CLFS), not the Physician Fee Schedule. Since the Protecting Access to Medicare Act (PAMA), the CLFS sets one national rate per code. There is no adjustment by MAC region or place of service.

The current Medicare CLFS rate for CPT 84550 is approximately $4.50, which makes it a low-reimbursement but high-volume chemistry code. Commercial payers typically reimburse at a multiple of the Medicare rate, often between 1.2x and 2.0x, though contracted rates vary.

Lab codes carry no RVUs, so check the CMS Clinical Laboratory Fee Schedule for the current national rate. Electronic remittance advice (ERA/835 files) from the clearinghouse shows the exact allowed amount per payer once claims adjudicate.

Place of service codes tell the payer where the test was performed and who is billing it. They don’t change the Medicare CLFS rate. The most common are:

• POS 11 (office): Specimen collected and processed in the provider’s own lab.
• POS 81 (independent laboratory): Reference lab billing independently under its own NPI.
• POS 22 (outpatient hospital): Hospital-based outpatient department; may be subject to hospital-specific fee schedule provisions.

ABN requirements for Medicare patients

Collect an Advance Beneficiary Notice of Noncoverage (ABN) before drawing blood for 84550 whenever Medicare may not cover the test. Common triggers include:

• The ordering diagnosis is not on the MAC’s covered diagnosis list.
• The test frequency exceeds LCD limits.
• The patient’s condition does not meet documented medical necessity criteria.

The ABN must be completed on form CMS-R-131 before the service is performed. If the patient elects to receive the test and Medicare denies the claim, the practice may bill the patient. Modifier GA signals that an ABN is on file. Modifier GZ signals that no ABN was obtained when one was required, which leaves the provider financially liable. Never use GZ intentionally, because that charge cannot be collected from the patient.

Top denial reasons for CPT code 84550 and how to fix them

Most 84550 denials fall into five patterns, and each has a specific fix. Knowing which pattern applies to a denied claim speeds up the appeal. Track denial reason codes on 84550 claims separately from general lab denials, because the fix differs from most other chemistry codes.

Each pattern maps to one check made before the claim leaves the practice, as the chart below shows.

• Missing or non-covered ICD-10: The claim was submitted without a diagnosis code, or the code used is not on the MAC’s covered list for 84550. Resolution: pull the applicable LCD, confirm the covered diagnosis list, and resubmit with a corrected ICD-10 that matches the documented indication. A reference of common denial codes helps your team decode the remittance reason quickly.
• No ABN on file: Medicare denied on medical necessity grounds and the practice cannot collect from the patient because no ABN was signed. Resolution: strengthen pre-collection protocols so ABN is obtained whenever the ordering diagnosis is outside the covered list.
• Incorrect specimen type: 84550 was billed for a urine specimen. Resolution: bill 84560 for urine uric acid, and never recode a urine test as 84550.
• Bundling into a panel: The payer applied a bundling edit because 84550 was submitted alongside 80053 on the same claim with identical diagnoses. Resolution: confirm that 84550 is not a component of the billed panel. Then resubmit with the clinical indication that called for a standalone uric acid test.
• Modifier 91 misuse: Modifier 91 was added to a same-day second claim for the same patient, with no documented clinical need for the repeat. Resolution: document the specific clinical reason requiring repeat testing in the chart before resubmitting with the modifier.

Billing tips for accurate CPT code 84550 claim submission

Clean claim submission for 84550 needs attention at each stage of the revenue cycle, from order entry to the day the ERA posts. Treat each chemistry code as a distinct billing event with its own documentation and eligibility checks. Folding lab claims into the general batch unchecked is how small errors repeat.

• Verify insurance eligibility before the draw: Confirm that the patient’s plan covers standalone chemistry testing and that there are no frequency limitations on uric acid. Checking eligibility at the point of order reduces avoidable ABN situations and patient balance disputes.
• Confirm CLIA certification status: If your practice runs 84550 in-house, confirm that your CLIA certificate covers the test system you use. A certificate of waiver covers only waived point-of-care devices billed with QW. Billing for a test your certificate does not authorize is a compliance violation regardless of payer.
• Match ICD-10 to the chart note before submission: The diagnosis code on the claim must match a documented indication in the encounter note. That note must share the claim’s date of service. Retroactively adding a diagnosis to justify a test that was ordered for an undocumented reason creates audit exposure.
• Use payer-specific LCD when available: The national Medicare policy provides a baseline, but MAC-specific LCDs can add or remove covered indications. Retrieve the LCD from your MAC’s provider portal and build it into your team’s coding reference.
• Bill 36415 separately: If your office performs the venipuncture, bill 36415 alongside 84550 on the same claim. The two are not bundled in current CCI edits, and failing to bill collection costs the practice legitimate revenue.

How claims management software prevents 84550 denials

Most 84550 denials start before the claim exists. A provider orders the test, the diagnosis sits in a free-text note, and billing staff key the code in later.

Claims management software in a practice management system like Pabau builds the claim from the encounter instead. The diagnosis attached to the lab order carries onto the claim, and 36415 and 84550 go out together on one encounter claim.

Claims then submit electronically through Claim.MD, Pabau’s clearinghouse integration, which connects to thousands of US payers. Remittance files post back against the same claim, so your team sees a denied 84550 line and its reason code without chasing paper.

Streamline your lab billing with Pabau

Pabau’s claims management tools help you submit 84550 and related chemistry codes with the right ICD-10 pairings attached, reducing denials before they happen. See how Pabau handles lab billing workflows from order to ERA.

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Conclusion

Treat 84550 as a documentation task that happens before the draw. When the chart names a covered diagnosis and the ABN question is settled first, the claim itself is routine.

The trade-off is the payment. At about $4.50 per test, a denied 84550 line is rarely worth the staff time to appeal, so prevention pays better than rework. Book a demo to see how Pabau carries the diagnosis from the lab order onto every lab claim.

Continue your research

Need guidance on clearinghouse submission for lab codes? Claim.MD clearinghouse overview explains how electronic lab claims route through the clearinghouse to payers, including real-time eligibility checks before submission.

Want to understand what happens after a clean claim leaves the practice? Medical billing fundamentals walks through the full claim lifecycle, from charge capture to payment posting, with practical guidance for in-house billing teams.

Dealing with recurring denials across multiple codes? Medical billing compliance practices covers the audit trail documentation requirements that protect practices during payer reviews and post-payment audits.

Billing the blood draw too? CPT code 36415 explains venipuncture billing, the collection service that usually rides on the same claim as 84550.

Need a system for working lab denials? Denial management in healthcare sets out how to track, appeal and prevent recurring claim denials.

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