Summary & Overview

CPT 88350: Immunofluorescent Single Antibody Stain

CPT code 88350 defines a single-antibody immunofluorescent staining procedure used by pathology laboratories to detect autoimmune disease markers or infectious organisms in tissue or cellular specimens. As a focused laboratory pathology service, it is a critical diagnostic tool for confirming immune-mediated processes and certain infections, influencing downstream clinical management and specialist referral.

This analysis covers national payer practices including Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context and service delivery settings, common modifiers and billing considerations provided as reference, and what typical coverage patterns and coding relationships are pertinent for lab and pathology services. The report summarizes benchmarks where available, highlights coding interactions relevant to follow-up or sequential staining procedures, and outlines areas where policy updates or payer-specific rules commonly affect claims processing.

The content is intended for billing professionals, laboratory directors, and health policy analysts seeking a concise, national-level briefing on CPT code 88350, its clinical role, and the payer landscape affecting its reimbursement and utilization.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare88350CPTImmunofluorescencePathologyLaboratoryAutoimmune diagnosticsInfectious disease testingSpecimen processing

Billing Code Overview

CPT code 88350 describes an immunofluorescent study using a single antibody stain performed by a pathology analyst to detect autoimmune disease or an infectious organism in a tissue or cellular sample. This code specifically represents the procedure when a single antibody stain is applied following an initial stain with a different antibody.

Service type: Immunofluorescence laboratory procedure (single antibody stain following an initial stain)
Typical site of service: Hospital pathology laboratories, independent clinical laboratories, and outpatient surgical pathology or biopsy specimen processing sites

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 52-year-old patient with a history of progressive renal dysfunction and proteinuria undergoes a kidney biopsy to evaluate for possible autoimmune glomerulonephritis. Fresh-frozen and paraffin-embedded tissue are submitted to the pathology laboratory. The laboratory performs an initial immunofluorescent stain with an antibody against immunoglobulin G (IgG). A second, different antibody (for example, complement component C3 or light chain kappa/lambda) is required to further characterize immune complex deposition. The histology technician documents tissue adequacy and requests additional single-antibody immunofluorescent staining. The medical laboratory analyst performs a second, single antibody immunofluorescent procedure on the same specimen to detect the alternate antigen, generating images and a diagnostic report for the renal pathologist. Results are used by the clinician to guide immunosuppressive therapy decisions.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the professional (interpretation) portion of the immunofluorescent study.
`51`	Multiple procedures	Use when multiple unrelated CPT pathology procedures are reported on the same day for the same patient.
`52`	Reduced services	Use when the immunofluorescent procedure is partially completed or limited in scope.
`59`	Distinct procedural service	Use when the single-antibody stain is a distinct service from other laboratory procedures on the same specimen.
`76`	Repeat procedure by same physician	Use when the same laboratory repeats the single-antibody stain on the same day.
`77`	Repeat procedure by another physician/lab (not in raw list)	Data not available in the input.
`90`	Reference (outside) laboratory	Use when the immunofluorescent stain is performed by an outside reference lab and results are reported back.
`91`	Repeat clinical diagnostic lab test	Use when a repeat immunofluorescent stain is performed for verification of results.
`TC`	Technical component	Use when billing only the technical component (staining, imaging) of the study.
`QK`	Laboratory performing physician certification waived (CLIA)	Use when the performing laboratory meets specific CLIA criteria (payer-specific).
`QX`	Modifier for certified lab personnel (CLIA)	Use when the test was performed by a CLIA-certified laboratory person as required by payer rules.
`QY`	Laboratory test ordered by a physician (CLIA)	Use when the laboratory test meets requirements for a physician ordering the test per payer rules.
`XE`	Separate encounter, a different encounter	Use when the single-antibody stain was performed during a separate encounter from other services.

Taxonomy Code	Specialty	Notes
207P00000X	Pathology	Anatomic/clinical pathologists interpret immunofluorescence studies.
207L00000X	Clinical Laboratory	Clinical laboratory directors and high-complexity lab personnel oversee staining and reporting.
2080P0200X	Nephrology	Nephrologists request renal immunofluorescence for glomerular disease workup.
207K00000X	Hematopathology	Hematopathologists may request/interpret immunofluorescence for hematologic tissue specimens.
207H00000X	Dermatopathology	Dermatopathologists frequently use immunofluorescence for autoimmune skin disease evaluation.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`N00.0`	Acute nephritic syndrome with diffuse membranous glomerulonephritis	Immunofluorescence helps detect immune complex and complement deposition in glomeruli.
`N03.2`	Chronic nephritic syndrome with diffuse membranous glomerulonephritis	Used to evaluate chronic immune-mediated glomerular injury via antibody localization.
`L93.0`	Discoid lupus erythematosus	Direct immunofluorescence of skin can identify granular immunoglobulin and complement along the dermal-epidermal junction.
`L93.9`	Lupus erythematosus, unspecified	Immunofluorescence aids in diagnosing cutaneous lupus variants.
`M32.9`	Systemic lupus erythematosus, unspecified	Renal immunofluorescence is integral in lupus nephritis classification and management.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`88342`	Immunohistochemistry or immunocytochemistry, per single antibody stain	Often performed on paraffin sections alongside immunofluorescence to characterize antigen expression.
`88341`	Immunohistochemistry or immunocytochemistry, per single antibody stain, manual	Alternative technique to `88342`; may be used when fluorescence is not indicated.
`88312`	Special stains, each additional procedure (e.g., direct immunofluorescence components)	Used for ancillary special stains that complement the single-antibody immunofluorescent study.
`88305`	Level IV surgical pathology, gross and microscopic examination	Often billed for the initial tissue pathology examination that precedes targeted immunofluorescent staining.
`88350`	Immunofluorescent study, single antibody stain (listed code)	The procedure for performing an additional single antibody stain after an initial stain with a different antibody.