Summary & Overview

CPT 84285: Silica (Silicon Dioxide) Blood Measurement

CPT code 84285 identifies a laboratory assay that measures silica (silicon dioxide) in patient blood. This test is clinically relevant for evaluating potential occupational or environmental exposure to silica and for monitoring suspected silica-related toxicity. Nationally, accurate coding for silica testing supports appropriate laboratory routing, public health tracking of exposures, and billing consistency across payers.

Key payers addressed in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication provides a concise overview of coding expectations, common billing modifiers, and payer coverage patterns where available, along with clinical context on when silica measurement is ordered.

Readers will learn the clinical purpose of the assay, typical service settings, and which payers are commonly involved in coverage decisions. The report summarizes benchmark considerations, highlights policy-relevant points affecting laboratory reimbursement and claim adjudication, and provides a reference for billing staff, laboratory managers, and compliance officers. Data not available in the input is noted where applicable.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicareCPT 84285silica testinglaboratorytoxicologyoccupational healthblood assayclinical laboratorybilling

Billing Code Overview

CPT code 84285 describes a laboratory measurement of silica (silicon dioxide), typically performed on a patient blood specimen. This test quantifies silica concentration to assess exposure or toxicity related to occupational or environmental sources.

Service type: Clinical laboratory testing
Typical site of service: Clinical laboratory or hospital laboratory setting

Clinical & Coding Specifications

Clinical Context

A 48-year-old construction worker with a history of chronic cough and dyspnea is evaluated for possible occupational silica exposure. The clinician orders a serum silica (silicon dioxide) quantitative assay to assess recent exposure and systemic absorption. The patient presents to an outpatient phlebotomy laboratory in a hospital-owned clinical laboratory. A trained phlebotomist collects a blood specimen using standard venipuncture technique, labels the specimen with two patient identifiers, and forwards it to the hospital chemistry/toxicology laboratory. A laboratory analyst performs sample preparation and a quantitative measurement of silica using an appropriate method (for example, inductively coupled plasma mass spectrometry or atomic absorption), documents results in the laboratory information system, and issues a report to the ordering pulmonologist and the occupational medicine clinic. The laboratory report includes numeric silica concentration, reference ranges, and interpretive comments if indicated. Typical workflow steps: order placed by clinician → specimen collection in outpatient lab or hospital draw station → specimen accessioning and processing by laboratory technologist → analytic measurement by laboratory analyst → result verification and reporting → clinician receives results for patient management or occupational health reporting.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the professional interpretation/analysis component separate from the technical component when both are split-billed.
`TC`	Technical component	Use when billing only the technical component (equipment, technician time, reagents) of the laboratory test.
`90`	Reference (outside) laboratory	Use when the specimen is sent to an outside laboratory and billed by the referring lab.
`QX`	Modifier for physician assistant services — assistant at surgery (CMS)	Use when a qualified non-physician practitioner performed services under supervision and payer requires this modifier for lab-related ordering/billing contexts (payer-specific).
`91`	Repeat clinical diagnostic laboratory test (not listed in raw modifiers)	Data not available in the input.
`52`	Reduced services	Use when the service performed was partially reduced or not completed as originally planned (limited processing).
`53`	Discontinued procedure	Use when specimen collection or testing was discontinued and partial work was performed.
`90`	Reference (outside) laboratory	Use when testing was performed by an outside reference laboratory and the billing reflects that arrangement.
`11`	Billing and coding maintenance — unspecified (commonly used for office visit?)	Use when reporting return to adjust billing for demonstration of usual, customary service (payer-dependent).
`26`	Professional component	Use when only the interpretation/analysis and professional oversight are billed (split billing).

Taxonomy Code	Specialty	Notes
`207Q00000X`	Clinical Pathology	Laboratory directors and clinical pathologists overseeing analytic methods and result interpretation.
`363A00000X`	Clinical Laboratory	Medical laboratory technologists/technicians and laboratory analysts performing the assay.
`207R00000X`	Pulmonary Disease	Ordering pulmonologists receiving results for management of occupational lung disease.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`J62.8`	Pneumoconiosis due to other dust containing silica	Direct occupational lung disease from silica exposure; silica assay may support exposure assessment.
`J62.0`	Pneumoconiosis due to talc dust containing silica	Relevant when mixed dust exposures include silica; laboratory confirmation of silica burden may be relevant.
`J61`	Pneumoconiosis due to silica dust	Classic diagnosis for chronic silica inhalation; serum silica testing may be part of occupational evaluation.
`Z57.3`	Occupational exposure to silica	Work-related exposure code used in conjunction with testing for surveillance and reporting.
`R06.02`	Shortness of breath	Symptom code commonly present in patients with suspected silica-related lung disease prompting testing.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80061`	Lipid panel; includes total cholesterol, HDL, and triglycerides	Often ordered concurrently in occupational health panels but not directly related to silica testing; represents routine chemistry panels performed in the same laboratory workflow.
`84443`	Thyroid stimulating hormone (TSH)	Common routine lab often ordered during systemic exposure evaluation or baseline health assessment in occupational evaluations.
`36415`	Collection of venous blood by venipuncture	Specimen collection procedure performed immediately before `84285` testing; necessary prerequisite for the assay.
`86003`	Allergen specific IgE, quantitative	Represents specialized immunology testing sometimes performed in occupational evaluations; performed in similar reference laboratory settings.