Laboratory Billing Guide: How to Bill Lab Tests Without Getting Flagged for Audits
Laboratory billing is one of the most compliance-sensitive areas of medical billing. The OIG consistently lists laboratory services among its top audit priorities, and the penalties for improper lab billing — from simple panel unbundling to fraudulent test ordering — can be severe. At the same time, many practices unknowingly leave lab revenue uncollected by using incorrect codes or missing billable services entirely.
This guide covers the most commonly billed lab CPT codes, the compliance rules that every practice must follow, and the specific red flags that trigger OIG lab billing audits.
Who Bills for Laboratory Services?
Before reviewing specific codes, it is essential to understand who is authorized to bill for laboratory services. There are three scenarios:
- Physician Office Laboratory (POL): The practice draws the specimen, performs the test in-office, and bills for the technical component. Requires a CLIA certificate at the appropriate level for the tests performed.
- Reference Lab: The practice draws the specimen, sends it to an outside lab, and the reference lab bills for the testing. The physician may bill a separate specimen collection fee if applicable.
- Hospital Outpatient Lab: The hospital bills for the lab services as part of the outpatient facility fee. The physician typically does not bill separately for lab interpretation unless it is a complex interpretation service (such as pathology).
CLIA Compliance: Any practice performing laboratory tests in-office must have the appropriate CLIA certificate. Waived tests (simple dipstick urinalysis, finger-stick glucose) require a Certificate of Waiver. Moderately complex tests require a Certificate of Compliance or Accreditation. Performing tests beyond your CLIA certificate level is a serious compliance violation.
Most Commonly Billed Laboratory CPT Codes
Routine Chemistry Panels
- 80047 — Basic metabolic panel (calcium, ionized) — 8 components
- 80048 — Basic metabolic panel — 8 components (total calcium)
- 80050 — General health panel — includes 80053, CBC with differential, and TSH
- 80053 — Comprehensive metabolic panel — 14 components including BMP components plus liver function, total protein, albumin
- 80061 — Lipid panel — total cholesterol, HDL cholesterol, triglycerides (LDL is calculated)
Hematology
- 85025 — Blood count, complete (CBC), automated, and automated differential WBC count
- 85027 — CBC, automated, without differential
- 85610 — Prothrombin time (PT)
- 85730 — Thromboplastin time, partial (PTT)
- 85025 — CBC with automated differential
Common Individual Chemistry Tests
- 82947 — Glucose; quantitative, blood
- 83036 — Hemoglobin A1c (glycated hemoglobin)
- 84443 — Thyroid stimulating hormone (TSH)
- 84480 — Triiodothyronine (T3), total
- 84439 — Thyroxine (T4), free
- 82728 — Ferritin
- 82306 — Vitamin D, 25-hydroxy
- 82607 — Vitamin B12 (cyanocobalamin)
- 82746 — Folic acid, serum
Urinalysis
- 81000 — Urinalysis, by dip stick or tablet reagent — non-automated, with microscopy
- 81001 — Urinalysis, automated, with microscopy
- 81002 — Urinalysis, by dip stick — without microscopy (waived test)
- 81003 — Urinalysis, automated, without microscopy
Microbiology and Infectious Disease
- 86592 — Syphilis test, qualitative (RPR)
- 86703 — HIV-1 and HIV-2 antibody testing, combined
- 87491 — Chlamydia trachomatis, amplified probe technique (NAAT)
- 87591 — Neisseria gonorrhoeae, amplified probe technique (NAAT)
- 87804 — Influenza virus antigen(s), direct observation methodology (rapid flu)
- 87880 — Streptococcus, group A, direct optical observation (rapid strep)
- 87426 — SARS-CoV-2 antigen detection
- 87635 — SARS-CoV-2 amplified probe technique (PCR)
Critical Lab Billing Compliance Rules
Urine Drug Screen Billing — The Highest-Risk Lab Service
Urine drug testing (UDT) is one of the most scrutinized lab services in the OIG's enforcement program. Practices that order excessive drug screens — particularly pain management, addiction medicine, and behavioral health practices — face significant audit risk.
- 80305 — Drug test(s), any number of drug classes, urine, any number of devices or procedures — read by direct optical observation
- 80306 — Drug test(s) — read by instrument-assisted direct optical observation
- 80307 — Drug test(s) — presumptive, any number of drug classes, by instrument chemistry analyzers
- 80320–80377 — Definitive drug testing codes by drug class
UDT Compliance Rule: Every urine drug screen must be ordered based on an individual clinical assessment of the patient — not as a blanket policy for all patients of a certain type. The medical record must document the specific clinical reason the test was ordered. Ordering presumptive and definitive testing on every patient every visit without individual clinical justification is a major OIG enforcement target.
How HNA Protects Your Lab Billing
HNA's coding team reviews every lab claim before submission to confirm the correct panel or component codes, verify medical necessity ICD-10 linkage, check for panel unbundling violations, and ensure proper place of service coding. For clients in high-risk specialties, we conduct quarterly lab billing audits to identify patterns before they become audit targets.
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