Summary & Overview

CPT 82105: Alpha–Fetoprotein Quantitative Assay

CPT code 82105 represents a quantitative laboratory assay for alpha–fetoprotein (AFP), a fetal glycoprotein that can be elevated in certain malignancies and liver disorders when measured later in life. This test supports diagnostic evaluation, oncology monitoring, and prenatal screening in clinical practice. Nationally, AFP measurement is an established laboratory service with implications for cancer surveillance and maternal-fetal medicine, making accurate coding essential for clinical workflows and claims processing.

Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context, typical sites of service, and which payers commonly reimburse AFP testing. The publication summarizes standard billing considerations, common modifier usage listed for this code, and contextual clinical applications of AFP measurement.

This summary equips clinicians, laboratory administrators, and billing professionals with a clear description of CPT code 82105, the clinical scenarios in which the test is used, and the payer landscape to expect for routine claims submission. Data not available in the input will be noted where applicable in other sections.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicareCPT 82105alpha-fetoproteinlaboratory testclinical laboratoryoncology testingprenatal screeningquantitative assaylab billing

Billing Code Overview

CPT code 82105 measures the quantitative level of alpha–fetoprotein (AFP) in a patient specimen. AFP is a glycoprotein produced during fetal development; elevated or abnormal levels in later life can be associated with certain tumors and liver disease.

Service type: Clinical laboratory quantitative immunoassay
Typical site of service: Hospital or independent clinical laboratory, outpatient laboratory draw sites, and specialty oncology or prenatal testing laboratories

Clinical & Coding Specifications

Clinical Context

A 32-year-old pregnant woman presents for routine prenatal screening at 15 weeks' gestation. Her obstetrician orders a maternal serum alpha‑fetoprotein (MSAFP) quantitative assay to evaluate fetal neural tube defect risk and to contribute to second‑trimester aneuploidy screening. A phlebotomy technician collects a serum sample which is sent to the clinical laboratory. The laboratory analyst performs the quantitative measurement of alpha‑fetoprotein using an immunoassay platform, documents the numeric concentration and reference range, and posts a result in the electronic medical record with interpretive comment regarding gestational age‑specific norms. Results are reviewed by the ordering obstetrician, who integrates the value with ultrasound findings and other screening tests to determine need for further diagnostic testing.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing physician interpretation or professional oversight separate from the technical lab component if applicable in composite billing arrangements.
`TC`	Technical component	Use when billing only the technical component (laboratory performing the assay) without physician interpretation.
`90`	Reference (outside) laboratory	Use when the specimen is sent to an outside independent laboratory that will bill separately.
`91`	Repeat clinical diagnostic laboratory test	Use when the test is repeated on the same day for the same patient to verify prior result.
`59`	Distinct procedural service	Use when a separate and distinct laboratory service is performed that is not normally billed together with another service.
`52`	Reduced services	Use when the lab performs a modified or partial procedure resulting in reduced service.
`53`	Discontinued procedure	Use when specimen collection or testing was started but discontinued and cannot be completed.
`90`	Reference (outside) laboratory	Use when testing is performed by an outside lab that bills independently.
`91`	Repeat clinical diagnostic laboratory test	Use when a repeat test is clinically indicated for result confirmation.
`QW`	CLIA waived test	Use only if the alpha‑fetoprotein assay was performed with a CLIA‑waived method in an applicable point‑of‑care setting.
`QK`	CLIA high complexity proficiency testing exempt	Use when applicable regulatory exemptions apply to the testing site.
`U1`	State or local payor modifier (example)	Use when payor requires a jurisdictional modifier for reporting or reimbursement tracking.

Taxonomy Code	Specialty	Notes
208100000X	Obstetrics & Gynecology	Ordering providers who commonly request MSAFP testing for prenatal screening.
207P00000X	Pathology	Pathologists oversee laboratory testing and interpretive reporting.
363L00000X	Medical Laboratory Technologist	Laboratory professionals performing the assay and quality control.
207L00000X	Clinical Laboratory	Laboratory directors or clinical chemists responsible for assay validation.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`Z34.80`	Encounter for supervision of other normal pregnancy, unspecified trimester	Typical code used for routine prenatal screening encounters when MSAFP is ordered.
`Z36.0`	Encounter for antenatal screening for chromosomal anomalies	Used when maternal serum AFP is part of aneuploidy screening.
`O35.0XX0`	Maternal care for (suspected) fetal abnormality and damage, not applicable or unspecified	Used when elevated AFP raises concern for fetal anomaly requiring specialist management.
`Q00.9`	Anencephaly and similar malformations, unspecified	Neural tube defect that can cause elevated maternal AFP; used when confirmed.
`Q01.9`	Encephalocele, unspecified	Neural tube defect associated with abnormal AFP values; used when diagnosis established.
`C22.0`	Liver cell carcinoma	Alpha‑fetoprotein can be elevated in hepatocellular carcinoma; used when AFP is ordered for tumor monitoring.
`C71.9`	Malignant neoplasm of brain, unspecified	Certain tumors may produce AFP; included for evaluation of AFP in oncologic workup.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`81001`	Urinalysis, by dipstick or tablet reagent; automated, without microscopy	Often performed in prenatal visits alongside serum screening for baseline evaluation.
`36415`	Collection of venous blood by venipuncture	Specimen collection for serum alpha‑fetoprotein measurement; precedes the laboratory assay.
`84153`	Alpha‑fetoprotein; quantitative	Alternate CPT representation sometimes used for AFP testing in certain coding sets; directly describes the quantitative AFP assay.
`76801`	Ultrasound, pregnant uterus, real time with image documentation, fetal and maternal evaluation, limited (e.g., fetal heartbeat, placental location)	Performed when abnormal MSAFP prompts targeted ultrasound to evaluate gestational age and neural tube defects.
`74712`	MRI, pelvis; without contrast, fetal MR when indicated	Performed in selected cases after abnormal AFP and ultrasound findings to further evaluate fetal anomalies.