Strep Test Coding Guide: CPT Codes, Modifiers & Billing Best Practices

Accurate coding for streptococcal pharyngitis testing ensures proper reimbursement and compliance. Follow this stepwise approach:

1. Identify the Test Type

• Rapid Antigen Detection Test (RADT): Point-of-care, results in minutes.
• Throat Culture: Gold standard, 24–48 hours.
• Molecular (NAAT/PCR): High sensitivity, often same-day.

2. Determine Place of Service (POS)

POS codes (e.g., 11–Office, 22–Outpatient Hospital, 81–Independent Lab) affect payment.

3. Select the Correct CPT Code

CPT Code	Description
87880	Infectious agent detection by immunoassay with direct optical observation (e.g., rapid strep)
87071	Culture, bacterial; quantitative, aerobic with isolation and presumptive identification (throat culture)
87651	Infectious agent detection by nucleic acid (DNA/RNA); Streptococcus, Group A, amplified probe technique

4. Apply Modifiers When Appropriate

• Modifier 59: Distinct procedural service (e.g., strep test + office visit on same day).
• Modifier QW: CLIA-waived test (for RADT performed in-office).
• Modifier 91: Repeat clinical diagnostic laboratory test (same day).

5. Verify Payer Policies

• Check LCDs/NCDs for frequency limits, medical necessity criteria.
• Confirm CLIA certification matches test complexity.
• Document clinical indication (symptoms, exposure, outbreak).

Key Tips

• Use the most current CPT codebook (annual updates).
• Link diagnosis code (e.g., J02.0–Streptococcal pharyngitis) to the test.
• For negative RADT with high clinical suspicion, reflex culture is standard; code both if performed.

Accurate documentation supports medical necessity and audit defense.