Summary & Overview
CPT 85004: Automated Differential White Blood Cell Count
CPT code 85004 represents an automated differential white blood cell count performed on a blood smear, where a laboratory analyst reviews a slide and an automated system enumerates different white cell types. This test is a routine component of hematology testing used to evaluate infection, inflammation, hematologic disorders, and treatment response; it is widely ordered across hospitals, outpatient laboratories, and clinical settings, making accurate coding and coverage understanding important for national billing consistency.
Key payers included in this analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise clinical context for the service, standard sites of service, and an overview of payer coverage considerations. The publication outlines common billing practice elements, typical documentation expectations for laboratory differential counts, and operational notes relevant to labs and billing teams.
This summary provides benchmarks for how the service is classified in claims, an explanation of clinical relevance for ordering clinicians and coders, and a policy-oriented overview of payer coverage themes. Data not available in the input includes specific payer rates, associated taxonomies, ICD-10 diagnoses, and related procedure codes; those items are not included here.
Billing Code Overview
CPT code 85004 describes a laboratory procedure in which a lab analyst examines a patient’s blood smear on a slide and uses an automated system to determine counts for each type of white blood cell. This procedure is a form of automated differential white blood cell count performed on a blood smear, combining microscopic slide analysis with instrumentation to enumerate neutrophils, lymphocytes, monocytes, eosinophils, basophils, and other identifiable white cell types.
Service type: Laboratory diagnostic test (automated differential on blood smear)
Typical site of service: Clinical laboratory or hospital laboratory
Clinical & Coding Specifications
Clinical Context
A typical patient is a adult or pediatric outpatient presenting to a primary care clinic, urgent care, emergency department, or hospital inpatient unit with symptoms such as fever, malaise, cough, or suspected infection. The clinician orders a complete blood count with differential; a phlebotomist draws a blood specimen which is routed to the laboratory. In the lab, a technologist or lab analyst prepares a slide or loads the sample into an automated hematology analyzer that performs a white blood cell differential, enumerating neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Results are reviewed by the lab, validated, and reported to the ordering clinician to aid in diagnosis and management of infection, inflammation, hematologic disorders, medication effects, or monitoring of therapy (for example, chemotherapy or immunosuppression). Typical sites of service include outpatient clinics, urgent care centers, hospital laboratories, and reference laboratories. Workflow steps: order entry by clinician, specimen collection, specimen accessioning, analysis (manual review or automated differential), result validation, and result reporting into the medical record or lab information system.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier — standard reporting | Use as the base submission when no modifier applies |