Summary & Overview
CPT 81106: HPA-2 (T145M) Genetic Allele Analysis
CPT code 81106 represents a targeted molecular diagnostic test that analyzes the two common alleles of Human Platelet Antigen 2 (HPA–2), also known as T145M, using specimens such as blood or amniotic fluid. This code is used to document the technical laboratory process of identifying allele status for HPA‑2, a platelet antigen relevant in transfusion medicine, platelet alloimmunization, and select prenatal or perinatal evaluations. Nationally, availability and use of HPA genotyping have implications for transfusion safety, maternal‑fetal medicine, and specialized hematology services.
Key payers covered in the analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication summarizes payer coverage patterns, typical sites of service, and clinical contexts where the test is ordered. Readers will find a concise clinical context for when HPA‑2 (T145M) allele testing is clinically relevant, an overview of common billing considerations, and what elements are typically part of laboratory service lines offering this test.
This report does not provide state‑level specifics. Where payer policy or benchmark data are not available in the input, it is noted as such. The focus is on explaining the code, its clinical role, and the types of information readers can expect from deeper sections on coverage, billing modifiers, and operational considerations.
Billing Code Overview
CPT code 81106 describes a laboratory molecular test in which the technical component analyzes the genes of the two common alleles of Human Platelet Antigen 2 (HPA–2), also called T145M, using a specimen such as blood or amniotic fluid. This is a targeted genetic assay focused on identifying the HPA‑2 (T145M) allelic variants.
-
Service type: Molecular diagnostic laboratory test (genetic allele analysis)
-
Typical site of service: Clinical laboratory or hospital-based laboratory using patient specimens such as peripheral blood or amniotic fluid
Clinical & Coding Specifications
Clinical Context
A 32-year-old pregnant woman is referred to a maternal-fetal medicine clinic after routine prenatal blood work shows a history of previous neonatal alloimmune thrombocytopenia (NAIT) in a prior pregnancy. The obstetrician orders targeted platelet antigen genotyping to determine parental and fetal Human Platelet Antigen status. A phlebotomy technician collects a maternal blood specimen; when fetal genotype is needed and noninvasive methods are insufficient, amniocentesis may be performed and amniotic fluid sent to the molecular laboratory. In the molecular lab, a trained laboratory analyst performs the technical assay to determine the genotype of the two common alleles of Human Platelet Antigen 2 (HPA–2 / T145M). Results are reported to the ordering clinician and incorporated into prenatal counseling and intrapartum management planning, including platelet transfusion strategy if NAIT risk is identified. Typical workflow steps: order entry by clinician, specimen collection (blood or amniotic fluid), sample accessioning, DNA extraction, targeted HPA-2 genotyping assay run by the lab analyst, result verification by a supervising molecular pathologist or laboratory director, and release of results to the clinician and medical record.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the professional interpretation or supervision if the lab separates technical and professional components. |
59 | Distinct procedural service | When HPA-2 genotyping is a distinct service from separate procedures performed the same day (use cautiously for NCCI compliance).