CPT 0039U: Anti–dsDNA High Salt/Avidity Assay for SLE Activity

CPT code 0039U designates a Proprietary Laboratory Analyses (PLA) assay: the University of Washington’s anti–dsDNA high salt/avidity test, which identifies salt‑resistant antibodies to double‑stranded DNA and has predictive value for systemic lupus erythematosus (SLE) disease activity. As a PLA code, 0039U represents a single manufacturer‑ or laboratory‑specific diagnostic and is used to uniquely identify that test for billing and tracking.

Key payers in scope for national coverage and reimbursement considerations include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find context on the clinical purpose of the assay, the service and site of service where it is typically performed, and what inclusion as a PLA code implies for coding precision. The publication also outlines common modifier usage (provided in the input) and indicates where data were not supplied.

This summary serves clinicians, laboratory administrators, and billing professionals seeking a concise reference on CPT code 0039U: what the code represents, why it matters clinically for SLE monitoring, and which major national payers are relevant for coverage discussions. Data not available in the input are noted where applicable; this piece does not provide state‑level specifics or actionable reimbursement advice.

Billing Code Overview

CPT code 0039U is a Proprietary Laboratory Analyses (PLA) code that describes a specific laboratory test developed and reported by the University of Washington, Department of Laboratory Medicine. The test is an anti–dsDNA, high salt/avidity assay that detects salt‑resistant antibodies to double‑stranded DNA, a marker that is predictive of systemic lupus erythematosus disease activity.

Service Type: Proprietary laboratory diagnostic test (specialty immunology assay)

Typical Site of Service: Clinical laboratory / hospital laboratory or reference lab

Data not available in the input.

Clinical Context

A 34-year-old female with known systemic lupus erythematosus (SLE) presents to a rheumatology clinic with increasing joint pain, fatigue, low-grade fever, and new onset hematuria. The treating rheumatologist orders specialized laboratory testing to evaluate disease activity and risk of renal involvement. The University of Washington Department of Laboratory Medicine performs the proprietary anti–dsDNA, high salt/avidity assay described by 0039U.

In the clinical workflow: the provider collects a serum specimen during the outpatient visit or inpatient admission and sends it to the reference laboratory. The laboratory performs the salt-resistant (high salt/avidity) anti–double-stranded DNA antibody test. Results are reported to the ordering clinician and integrated into the medical record to guide assessment of SLE activity and potential renal flare. Typical sites of service include hospital outpatient laboratories, independent reference laboratories, and hospital inpatient or outpatient pathology/laboratory departments.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the professional interpretation component if separated from the technical lab component.

Taxonomy Code	Specialty	Notes
`207RH0000X`	Rheumatology	Ordering specialty for SLE activity assessment.
`207L00000X`	Clinical Pathology	Laboratory specialty performing serologic and immunologic testing.
`207K00000X`	Pediatrics (Rheumatology as pediatric subspecialty often 207RP...)	Pediatric rheumatologists order this test for juvenile SLE.
`2080P0200X`	Hospitalist	May order testing for inpatient evaluation of SLE flare.
`363A00000X`	Clinical Laboratory Director/Pathology	Responsible for laboratory operations and reporting.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`M32.10`	Systemic lupus erythematosus, organ or system involvement unspecified	Primary diagnosis indicating SLE; anti-dsDNA avidity testing assesses disease activity.
`M32.11`	Systemic lupus erythematosus with organ or system involvement, renal involvement	High clinical relevance: anti–dsDNA high-avidity antibodies correlate with lupus nephritis risk and activity.
`M32.9`	Systemic lupus erythematosus, unspecified	Used when SLE is diagnosed but specifics are not listed; test assists in activity evaluation.
`R31.0`	Gross hematuria	Symptom that may prompt evaluation for lupus nephritis and ordering of `0039U`.
`N05.9`	Unspecified nephrotic syndrome	Renal manifestations prompting serologic evaluation for SLE-related nephritis.
`R53.83`	Other fatigue	Common symptom in SLE flares; supportive clinical context for ordering disease-activity testing.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80053`	Comprehensive metabolic panel	Commonly ordered concurrently to assess renal function and electrolytes when evaluating SLE activity and possible nephritis.
`85025`	Complete blood count (CBC) with automated differential	Often ordered alongside to evaluate cytopenias related to SLE or medication effects.
`86146`	Antinuclear antibody (ANA) quantitative or semi-quantitative	Common upstream screening test for autoimmune disease; may be performed earlier in the diagnostic algorithm.
`86152`	Antibodies to single-stranded DNA (ssDNA) or other specific autoantibodies (example)	Other autoantibody panels that can accompany `0039U` in immunologic evaluation.
`88305`	Level IV surgical pathology, gross and microscopic examination	May be relevant if renal biopsy is performed to confirm lupus nephritis; often paired in the broader diagnostic workflow.

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Summary & Overview