Summary & Overview
CPT 0312U: Avise® Lupus Proprietary Laboratory Assay
CPT code 0312U designates a Proprietary Laboratory Analyses (PLA) test — Avise® Lupus from Exagen, Inc. — that measures ten biomarkers, including eight IgG autoantibodies and two cell–bound complement activation products (CB–CAPs), to support the differential diagnosis of systemic lupus erythematosus (SLE). As a PLA code, 0312U applies only to this single manufacturer’s assay, reflecting the growing role of proprietary molecular diagnostics in autoimmune disease evaluation. Nationwide relevance stems from the clinical need for improved SLE diagnostic specificity and the policy implications of single-source lab codes for coverage and coding consistency.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context for the Avise® Lupus assay, typical sites of service, and the practical implications of a PLA-designated CPT code. The publication outlines coverage considerations across major national payers, common billing modifiers, and areas where payers commonly request supporting documentation. It also summarizes benchmarks and policy updates relevant to proprietary laboratory codes, and provides clarity on how 0312U fits into laboratory service lines and diagnostic workflows for suspected SLE.
Billing Code Overview
CPT code 0312U is a Proprietary Laboratory Analyses (PLA) code reported exclusively for the Avise® Lupus test developed by Exagen, Inc. The test uses a specimen such as serum, plasma, or whole blood to measure a panel of 10 biomarkers — eight IgG autoantibodies associated with systemic lupus erythematosus (SLE) and two cell–bound complement activation products (CB–CAPs) — to aid in the differential diagnosis of SLE. CB–CAPs are traces of cell-surface proteins activated as part of the complement immune system.
Service type: Proprietary laboratory diagnostic assay
Typical site of service: Clinical laboratory or hospital laboratory, with specimens collected in outpatient clinics or phlebotomy centers
Clinical & Coding Specifications
Clinical Context
A 34-year-old woman presents to a rheumatology clinic with persistent arthralgia, photosensitivity, intermittent oral ulcers, and a history of unexplained cytopenias. Initial screening tests (ANA, anti-dsDNA, complement levels) are equivocal. The rheumatologist orders 0312U (Avise® Lupus) using a serum specimen to measure eight IgG autoantibodies and two cell-bound complement activation products (CB–CAPs) to aid in the differential diagnosis of systemic lupus erythematosus (SLE). The clinical workflow: the patient has blood drawn in clinic or at an outpatient laboratory, the specimen is sent to the manufacturer’s laboratory for the proprietary assay, and results are returned to the ordering provider. Results are used in conjunction with clinical findings and other laboratory studies to support or refute an SLE diagnosis, inform additional testing, and guide follow-up planning.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier — standard reporting | Use when no special circumstances apply to the laboratory service |
26 | Professional component | Use if reporting separately the professional interpretation component when applicable (rare for PLAs) |
52 | Reduced services | Use if the test was partially performed or limited for clinical reasons |
53 | Discontinued procedure | Use if specimen collection or testing was attempted but discontinued for clinical reasons |
62 | Two surgeons | Use if procedural services requiring two surgeons are reported (not typical for lab tests; included per input list) |
78 | Return to operating room | Use for surgical cases returned to the OR (not typical for lab tests) |
80 | Assistant surgeon | Use when an assistant surgeon is involved (not typical for lab tests) |
AS | Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery | Use when applicable for assistant-at-surgery services (not typical for lab testing) |
QK | Medical direction of two, three, or four qualified individuals | Use when physician provides medical direction in applicable multi-operator services |
QX | CRNA service: medical direction by physician | Use when certified registered nurse anesthetist services are billed under direction (not typical for lab testing) |
QY | Qualified nonphysician anesthetist | Use for services by qualified nonphysician anesthetist (not typical for lab testing) |
TC | Technical component | Use if reporting only the technical component of the test (e.g., lab performs assay without professional interpretation) |
TG | Via interactive audio and video telecommunications system | Use when specimen collection or patient interaction occurs via telemedicine-supported services (limited applicability) |
FY | Inpatient family limited services (facility) | Use for facility billing nuances when applicable |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
207R00000X | Rheumatology | Ordering specialty most commonly responsible for SLE workup |
207L00000X | Allergy & Immunology | Specialists who may order autoimmune serologies and CB–CAP testing |
208D00000X | Clinical Pathology | Laboratory medicine physicians overseeing test performance and interpretation |
363LF0000X | Phlebotomy | Personnel performing specimen collection in outpatient settings |
261QM0800X | Internal Medicine | Primary care physicians who may order initial autoimmune evaluation |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
M32.9 | Systemic lupus erythematosus, unspecified | Primary diagnosis under evaluation; Avise® Lupus aids differential diagnosis |
M35.3 | Polymyalgia rheumatica | Differential for inflammatory symptoms; used when distinguishing autoimmune causes |
R00.0 | Tachycardia, unspecified | Non-specific symptom that may be present in systemic illness; supportive clinical data |
R53.1 | Weakness | Common presenting symptom prompting autoimmune evaluation |
R50.9 | Fever, unspecified | Systemic symptom that may prompt evaluation for SLE or other inflammatory disease |
D72.8 | Other specified disorders of white blood cells | Cytopenias or leukopenia can be associated with SLE and trigger further testing |
N08 | Glomerular damage in diseases classified elsewhere | Renal involvement may be evaluated when SLE is suspected |
L93.0 | Discoid lupus erythematosus | Cutaneous lupus subtype relevant to serologic evaluation and differential diagnosis |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
81025 | Urinalysis; microscopic only | Performed to evaluate hematuria or proteinuria when SLE is suspected |
80053 | Comprehensive metabolic panel | Common baseline lab to assess organ function in patients evaluated for SLE |
80061 | Lipid panel | May be ordered for cardiovascular risk assessment in SLE patients |
85025 | Complete blood count (CBC) with automated differential | Evaluates cytopenias commonly seen in SLE and informs differential diagnosis |
86163 | Antinuclear antibody (ANA) with titer and pattern | Common initial serologic test for suspected systemic autoimmune disease |
86038 | Antibody; rheumatoid factor | Ordered to assess alternative causes of inflammatory arthralgia |