CPT 0166U: LiverFASt™ Blood Biomarker Panel for Noninvasive Liver Staging

CPT code 0166U denotes the LiverFASt™ Proprietary Laboratory Analyses (PLA) test from Fibronostics, a blood‑based panel that measures 10 liver‑related biomarkers and uses a proprietary algorithm to estimate fibrosis stage, steatosis, and inflammatory activity without invasive procedures. As a PLA code, 0166U is unique to a single manufacturer's test and signals to payers and providers that the service includes both biomarker measurement and algorithmic interpretation.

Key payers referenced in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Coverage and coding policies for PLA tests can vary by payer; PLA codes are intended to improve transparency for novel, proprietary diagnostics and to facilitate payer review of clinical validity and utility.

Readers will find a concise overview of the clinical purpose of the test, the service setting for specimen collection and laboratory processing, and what payers typically consider when evaluating coverage for proprietary diagnostic algorithms. The publication also summarizes common billing considerations, including the PLA code designation and how that designation affects payer review processes. Data not available in the input: detailed payer policy language, reimbursement benchmarks, associated taxonomies, and specific ICD‑10 diagnoses tied to billing for this test.

Billing Code Overview

CPT code 0166U is a Proprietary Laboratory Analyses (PLA) code assigned specifically to the LiverFASt™ test from Fibronostics. The code applies to a single, manufacturer‑specific laboratory assay that analyzes a blood specimen for 10 liver‑related biomarkers and applies a proprietary algorithm to estimate liver fibrosis stage, steatosis (fatty liver), and inflammatory activity without invasive testing.

Service type: Laboratory diagnostic test with algorithmic interpretation (proprietary blood‑based biomarker panel)

Typical site of service: Clinical diagnostic laboratory or reference laboratory processing blood specimens; sample collection typically occurs in outpatient clinics, phlebotomy centers, or physician offices

Clinical Context

A 54-year-old patient with metabolic risk factors (type 2 diabetes and obesity) presents for evaluation of suspected chronic liver disease after abnormal liver chemistries and ultrasound showing hepatic steatosis. The clinician orders the proprietary LiverFASt™ blood test (0166U) to noninvasively estimate liver fibrosis stage, steatosis severity, and inflammatory activity using 10 serum biomarkers and an algorithmic analysis. A phlebotomy encounter is performed in an outpatient laboratory or clinic; the specimen is sent to the performing laboratory (Fibronostics) for the proprietary analysis. Results are returned to the ordering hepatologist or primary care provider and integrated with clinical assessment to guide monitoring, need for treatment, or referral for specialty care. Typical sites of service include outpatient clinic, ambulatory laboratory, or hospital outpatient phlebotomy services. The test is used when clinicians wish to avoid invasive biopsy, to triage patients for treatment or further imaging, or to monitor disease progression over time.

Coding Specifications

Modifier	Description	When to Use
`11`	Clinical laboratory/test performed	Use when reporting that the service was the usual, standard service provided by the billing laboratory or provider.

Taxonomy Code	Specialty	Notes
`207RH0000X`	Radiation Oncology	Not typically the ordering provider; included for taxonomy completeness.
`207Q00000X`	Infectious Disease	Infectious disease specialists may order liver disease testing when viral hepatitis is suspected.
`207L00000X`	Gastroenterology	Common ordering specialty for noninvasive liver assessment.
`208000000X`	Family Medicine	Common ordering specialty for initial evaluation and monitoring of fatty liver disease.
`207K00000X`	Internal Medicine	Common ordering specialty for chronic liver disease evaluation.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`K76.0`	Fatty (change of) liver, not elsewhere classified	Primary indication for noninvasive assessment of steatosis and fibrosis using `0166U`.
`K75.81`	Nonalcoholic steatohepatitis (NASH)	Indicates suspected inflammatory fatty liver disease where the test estimates inflammatory activity and fibrosis.
`K74.60`	Unspecified cirrhosis of liver	Relevant for staging fibrosis; test can help estimate the degree of fibrosis toward cirrhosis.
`B18.2`	Chronic viral hepatitis C	Viral hepatitis is a common cause of chronic liver injury; biomarker panels assist in staging and management decisions.
`E11.9`	Type 2 diabetes mellitus without complications	Metabolic comorbidity associated with fatty liver disease; commonly present in patients undergoing this testing.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Often performed immediately prior to `0166U` to obtain the blood specimen for testing.
`81025`	Urinalysis, non-automated, with microscopy	May be ordered in the same workup for metabolic comorbidities and baseline assessment.
`80076`	Hepatic function panel (includes several liver chemistries)	Commonly ordered alongside `0166U` to provide standard liver enzyme and function data that complement algorithmic biomarker results.
`87521`	Infectious agent detection by nucleic acid (e.g., hepatitis C)	Viral hepatitis testing is often performed in the differential diagnosis when interpreting liver biomarker panels.
`82546`	Creatinine; testing for renal function	Frequently performed in the same episode of care to assess renal function prior to potential medication decisions related to liver disease.

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Summary & Overview