Summary & Overview
CPT 86336: Inhibin A Assay for Prenatal Down Syndrome Screening
CPT code 86336 represents a laboratory assay for inhibin A used in prenatal serum screening to estimate fetal risk for Down syndrome. As part of multi-marker maternal screening protocols, this test contributes clinical information that can influence follow-up diagnostic decisions and prenatal care planning. Nationally, prenatal screening tests like the inhibin A assay are routinely ordered across obstetrics practices and clinical laboratories and are a common component of second-trimester aneuploidy risk assessment.
Key payers addressed in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Coverage policies for prenatal screening vary by payer, with differences in approved indications, bundled panels versus standalone testing, and prior authorization requirements. This publication provides a concise overview of billing and clinical context for the code and highlights the operational aspects relevant to laboratories and obstetrics providers.
Readers will find: a clear description of the service represented by CPT code 86336; typical sites of service and specimen collection procedure; a summary of payer coverage landscape and common billing modifiers; and guidance on where to find additional policy detail. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 86336 describes a laboratory assay measuring inhibin A levels in a maternal serum specimen. The test is performed to assess fetal risk for Down syndrome (trisomy 21) as part of prenatal screening.
Service type: Laboratory prenatal screening test
Typical site of service: Clinical laboratory or hospital laboratory; specimen collected from maternal venous blood via routine venipuncture
Clinical & Coding Specifications
Clinical Context
A 32-year-old pregnant patient at 15 weeks gestation presents for prenatal screening as part of a second-trimester maternal serum quad screen. The clinician orders measurement of inhibin A to help assess fetal risk for chromosomal abnormalities, specifically Down syndrome. A phlebotomist obtains a routine venous blood specimen during an outpatient obstetrics clinic visit. The sample is sent to the clinical laboratory where a medical technologist or lab analyst performs the 86336 assay to quantify serum inhibin A. Results are reported to the ordering obstetrician or maternal-fetal medicine specialist and incorporated into risk calculations alongside measured levels of alpha-fetoprotein, estriol, and human chorionic gonadotropin, and correlated with patient age and ultrasound findings. Typical sites of service include outpatient obstetrics/gynecology clinics, hospital outpatient laboratories, and independent clinical laboratories.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the professional interpretation component if applicable for lab reporting oversight. |
TC |