Summary & Overview
CPT 86361: Absolute CD4 Cell Count Test
CPT code 86361 represents an absolute CD4 cell count, a laboratory test that quantifies CD4 T-lymphocytes per microliter of blood to assess immune function in patients with HIV infection. Nationally, this test is a key clinical marker used for staging disease, guiding antiretroviral therapy decisions, and monitoring immune recovery or decline. Payer coverage and payment policies for CD4 testing influence access to timely monitoring and follow-up care for people living with HIV.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise review of clinical context for CD4 testing, typical sites of service where the test is performed, and the common modifiers associated with laboratory billing. The publication summarizes benchmark considerations and highlights policy and coverage elements that commonly affect reimbursement and utilization for laboratory services nationally.
This summary provides clinicians, laboratory managers, and policy analysts with a focused overview of CPT code 86361, what it measures, why it matters for patient management, and the types of payer policies that typically apply. Data not available in the input are noted where relevant in detailed sections.
Billing Code Overview
CPT code 86361 describes an absolute CD4 cell count performed by a laboratory analyst to measure the number of CD4 lymphocytes per microliter in a patient specimen, typically blood. This test assesses immune system function, commonly ordered to evaluate and monitor patients diagnosed with HIV infection.
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Service type: Clinical laboratory pathology test (absolute CD4 count)
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Typical site of service: Hospital laboratory, independent reference laboratory, or outpatient phlebotomy/clinic laboratory
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult or adolescent with known or suspected HIV infection undergoing routine immune monitoring. The patient presents to an outpatient clinic, infectious disease practice, or hospital phlebotomy lab for venipuncture. A provider orders an absolute CD4 cell count (86361) to quantify CD4+ T-lymphocytes per microliter of blood to assess immune status, guide antiretroviral therapy decisions, opportunistic infection prophylaxis, or monitor response to treatment. The clinical workflow: the provider documents the order and relevant diagnosis, the patient has blood drawn by phlebotomy staff, the specimen is transported to the laboratory, the lab analyst performs flow cytometry or equivalent methods to enumerate CD4 cells and reports the absolute count and percentage as applicable, and results are routed back to the ordering provider for interpretation and follow-up care.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | Default/No modifier | Use when no other modifier applies and standard billing is appropriate |
26 | Professional Component |