Summary & Overview
CPT 81266: STR Marker Testing for Additional Comparative Specimen
CPT code 81266 is an add-on molecular diagnostic laboratory code for technical testing of Short Tandem Repeat (STR) markers to compare genetic similarity between a patient and an additional comparative specimen beyond the first (for example, a second cord blood donor or an additional infant in multiple–birth zygosity testing). This service augments the primary comparative STR analysis coded by 81265 and is relevant for transplant donor verification, cord blood unit comparison, and zygosity confirmation in multiple births. Nationally, precise coding for add-on molecular tests like 81266 affects claims processing, laboratory payment, and documentation standards for genetic identity testing.
Key payers included in this analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context, payer coverage considerations, and typical billing practice around add-on STR testing. The publication covers benchmark considerations, common modifiers and billing elements used with add-on molecular laboratory services, and policy updates influencing molecular diagnostics reimbursement. It also provides clinical context on when additional comparative STR testing is clinically indicated and how it interfaces with primary STR comparative services.
Data not available in the input for associated taxonomies, specific ICD-10 codes, related CPT codes beyond 81265, and detailed payer-specific reimbursement rates.
Billing Code Overview
CPT code 81266 is an add-on molecular diagnostic laboratory service performed in conjunction with 81265. The service documents the technical laboratory testing of Short Tandem Repeat (STR) markers to compare genetic similarity between the patient and an additional comparative specimen beyond the first, such as a second cord blood donor or an additional infant in multiple–birth zygosity testing.
-
Service type: Molecular diagnostic laboratory test (STR marker evaluation)
-
Typical site of service: Clinical laboratory or reference molecular diagnostics laboratory
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A neonatal intensive care unit receives three infants from a multiple–birth pregnancy where zygosity (identical vs fraternal) is clinically relevant for counseling and transplant donor planning. The laboratory has already performed initial parent–infant or first comparative STR testing (81265) and now must process an additional comparative specimen (for example, a third infant or a second cord blood donor). The lab analyst performs the technical STR marker evaluation to compare genetic similarity between the patient and the additional specimen. Typical workflow: accessioning of the additional specimen, DNA extraction, PCR amplification of STR loci, capillary electrophoresis analysis, data comparison to the prior report, technical verification and documentation, and transmission of results to the ordering clinician. Typical site of service is a clinical molecular genetics laboratory, hospital laboratory, or specialty reference lab supporting neonatal, transplant, and forensic genetic services. The typical patient scenario is molecular zygosity testing for multiple–birth infants or comparison testing for an additional cord blood donor when more than one donor specimen requires STR analysis beyond the first comparative sample.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing for the interpretation/reporting by a laboratory director or pathologist separate from the technical lab work |