Summary & Overview

CPT 0446U: aiSLE DX Disease Activity Index, SLE Biomarker Panel

CPT code 0446U is a Proprietary Laboratory Analyses (PLA) code that represents the aiSLE® DX Disease Activity Index from Progentec Diagnostics Inc., an immunoassay-based plasma test measuring 10 biomarkers and producing an algorithmic risk score for systemic lupus erythematosus (SLE) disease activity. As a PLA code, 0446U identifies a single, manufacturer-specific laboratory test and matters nationally because it standardizes reporting for a proprietary SLE disease activity assay and supports clinical decision-making and utilization tracking.

Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will learn the clinical context of the assay, how the test is reported using a PLA CPT code, and the typical sites of service for specimen collection and analysis. The publication provides benchmarks and policy-oriented information relevant to coverage and coding practices, highlights the implications of PLA coding for lab-specific tracking, and outlines the clinical utility of algorithmic risk scoring for monitoring SLE activity. Data not available in the input is noted where payer-specific coverage policies, fee schedules, or related taxonomies and ICD-10 mappings are absent.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare0446UCPTProprietary Laboratory AnalysesSLEimmunoassaydisease activity indexlaboratory testingplasma biomarker panel

Billing Code Overview

CPT code 0446U is a Proprietary Laboratory Analyses (PLA) code specific to the aiSLE® DX Disease Activity Index from Progentec Diagnostics Inc. The test uses an immunoassay on a plasma specimen to measure 10 biomarkers related to systemic lupus erythematosus (SLE) and reports individual component values plus an algorithmic risk score for current disease activity. Results assist the ordering provider in measuring SLE disease activity and assessing treatments.

Service type: Clinical laboratory test (proprietary immunoassay with algorithmic interpretation)
Typical site of service: Clinical laboratory or outpatient phlebotomy site where plasma specimens are collected and sent to the performing laboratory for analysis.

Clinical & Coding Specifications

Clinical Context

A 34-year-old woman with established systemic lupus erythematosus (SLE) presents to her rheumatologist for routine disease activity assessment after a change in immunomodulatory therapy. The ordering provider requests the aiSLE® DX Disease Activity Index (0446U) from Progentec Diagnostics to objectively quantify current SLE activity using a plasma specimen. A trained phlebotomist collects the blood specimen during an outpatient clinic visit or at an ambulatory lab; the specimen is processed and shipped per the manufacturer's instructions to the performing laboratory. Results include individual biomarker values and an algorithmic risk score to help the clinician evaluate disease activity, compare response to recent therapy changes, and consider treatment adjustments.

Typical site of service is an outpatient clinic, ambulatory phlebotomy center, or hospital outpatient laboratory. The specimen collection and test ordering occur during the clinic visit; the laboratory performs the proprietary immunoassay and returns a report that the rheumatologist reviews in follow-up or during the same visit if rapid turnaround is available.

Coding Specifications

Modifier	Description	When to Use
`00`	Default/standard laboratory service	Use when no other modifier applies to the PLA test.
`26`	Professional component	Use if reporting only the professional interpretation component separate from technical processing (rare for PLA tests).
`52`	Reduced services	Use when the service is partially reduced or not fully performed.
`53`	Discontinued procedure	Use if specimen collection or testing was started but discontinued for clinical reasons.
`62`	Two surgeons	Generally not applicable to lab testing but used when two providers of record share responsibility; rarely used.
`78`	Unplanned return to the operating/procedure room	Not commonly used for this lab test; include only when clinically applicable.
`80`	Assistant surgeon	Not typically applicable to laboratory testing.
`AS`	Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery	Not commonly applicable to lab testing.
`QK`	Clinical laboratory fee schedule (CLFS) technical component performed by a separate entity	Use when distinguishing technical component billing under specific CLFS arrangements.
`QX`	Services performed by a CRNA with medical direction by a physician	Not applicable to this test but included when billing rules require CRNA modifiers.
`QY`	Medical direction of two or more concurrent anesthesia procedures	Not applicable to this lab test.
`TC`	Technical component	Use when reporting only the technical component (laboratory processing) if the professional component is billed separately.
`SH`	Physician or other qualified healthcare professional services in surgical hospice	Not typically applicable.
`SJ`	Private-payment laboratory services	Use when the test is performed and billed to a private entity under certain contractual arrangements.

Taxonomy Code	Specialty	Notes
`207R00000X`	Rheumatology	Ordering specialty that commonly manages SLE disease activity assessment and orders `0446U`.
`208D00000X`	Clinical Laboratory	Performing laboratory specialists responsible for processing and reporting the PLA test.
`207L00000X`	Allergy & Immunology	Specialists who may order SLE activity testing for autoimmune disease management.
`363LP0800X`	Phlebotomy	Personnel performing specimen collection in outpatient or ambulatory settings.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`M32.10`	Systemic lupus erythematosus, organ or system involvement unspecified	Direct indication for monitoring disease activity with `0446U`.
`M32.9`	Systemic lupus erythematosus, unspecified	General SLE diagnosis where disease activity assessment is clinically relevant.
`M32.0`	Drug-induced systemic lupus erythematosus	Used when assessing activity in suspected drug-induced SLE vs idiopathic SLE.
`M32.14`	Systemic lupus erythematosus with organ or systemic involvement, renal involvement	SLE with renal disease where objective activity indices inform treatment decisions.
`M32.0X`	Systemic lupus erythematosus manifestations (placeholder for variant codes)	Represents other SLE-specific codes used in clinical documentation to justify disease activity testing.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Venous blood collection commonly performed to obtain the plasma specimen for `0446U`.
`80053`	Comprehensive metabolic panel	Frequently ordered alongside disease activity testing to assess organ function and medication effects.
`85025`	Complete blood count (CBC) with automated differential	Often ordered concurrently to evaluate hematologic manifestations of SLE and help interpret disease activity.
`86038`	Antinuclear antibodies (ANA) by immunoassay	Common immunologic test in SLE workup and monitoring; may be ordered in the same clinical workflow.
`87086`	Culture, bacterial; urine, quantitative (if applicable)	Ordered when infection is a consideration in differentiating disease flare versus infection (contextual adjunct test).

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Summary & Overview

CPT 0446U: aiSLE DX Disease Activity Index, SLE Biomarker Panel

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare0446UCPTProprietary Laboratory AnalysesSLEimmunoassaydisease activity indexlaboratory testingplasma biomarker panel

Billing Code Overview

Service type: Clinical laboratory test (proprietary immunoassay with algorithmic interpretation)
Typical site of service: Clinical laboratory or outpatient phlebotomy site where plasma specimens are collected and sent to the performing laboratory for analysis.

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Modifier	Description	When to Use
`00`	Default/standard laboratory service	Use when no other modifier applies to the PLA test.
`26`	Professional component	Use if reporting only the professional interpretation component separate from technical processing (rare for PLA tests).
`52`	Reduced services	Use when the service is partially reduced or not fully performed.
`53`	Discontinued procedure	Use if specimen collection or testing was started but discontinued for clinical reasons.
`62`	Two surgeons	Generally not applicable to lab testing but used when two providers of record share responsibility; rarely used.
`78`	Unplanned return to the operating/procedure room	Not commonly used for this lab test; include only when clinically applicable.
`80`	Assistant surgeon	Not typically applicable to laboratory testing.
`AS`	Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery	Not commonly applicable to lab testing.
`QK`	Clinical laboratory fee schedule (CLFS) technical component performed by a separate entity	Use when distinguishing technical component billing under specific CLFS arrangements.
`QX`	Services performed by a CRNA with medical direction by a physician	Not applicable to this test but included when billing rules require CRNA modifiers.
`QY`	Medical direction of two or more concurrent anesthesia procedures	Not applicable to this lab test.
`TC`	Technical component	Use when reporting only the technical component (laboratory processing) if the professional component is billed separately.
`SH`	Physician or other qualified healthcare professional services in surgical hospice	Not typically applicable.
`SJ`	Private-payment laboratory services	Use when the test is performed and billed to a private entity under certain contractual arrangements.

Taxonomy Code	Specialty	Notes
`207R00000X`	Rheumatology	Ordering specialty that commonly manages SLE disease activity assessment and orders `0446U`.
`208D00000X`	Clinical Laboratory	Performing laboratory specialists responsible for processing and reporting the PLA test.
`207L00000X`	Allergy & Immunology	Specialists who may order SLE activity testing for autoimmune disease management.
`363LP0800X`	Phlebotomy	Personnel performing specimen collection in outpatient or ambulatory settings.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`M32.10`	Systemic lupus erythematosus, organ or system involvement unspecified	Direct indication for monitoring disease activity with `0446U`.
`M32.9`	Systemic lupus erythematosus, unspecified	General SLE diagnosis where disease activity assessment is clinically relevant.
`M32.0`	Drug-induced systemic lupus erythematosus	Used when assessing activity in suspected drug-induced SLE vs idiopathic SLE.
`M32.14`	Systemic lupus erythematosus with organ or systemic involvement, renal involvement	SLE with renal disease where objective activity indices inform treatment decisions.
`M32.0X`	Systemic lupus erythematosus manifestations (placeholder for variant codes)	Represents other SLE-specific codes used in clinical documentation to justify disease activity testing.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Venous blood collection commonly performed to obtain the plasma specimen for `0446U`.
`80053`	Comprehensive metabolic panel	Frequently ordered alongside disease activity testing to assess organ function and medication effects.
`85025`	Complete blood count (CBC) with automated differential	Often ordered concurrently to evaluate hematologic manifestations of SLE and help interpret disease activity.
`86038`	Antinuclear antibodies (ANA) by immunoassay	Common immunologic test in SLE workup and monitoring; may be ordered in the same clinical workflow.
`87086`	Culture, bacterial; urine, quantitative (if applicable)	Ordered when infection is a consideration in differentiating disease flare versus infection (contextual adjunct test).