Summary & Overview
CPT 80189: Itraconazole Quantitative Assay, Therapeutic Drug Monitoring
CPT code 80189 represents a quantitative laboratory assay to measure itraconazole levels in patient specimens (for example, serum). Therapeutic drug monitoring of itraconazole is clinically important for optimizing antifungal therapy, especially in immunocompromised patients where subtherapeutic exposure risks treatment failure and supratherapeutic exposure raises toxicity concerns. Nationally, this code captures a specialized laboratory service used by hospitals, outpatient clinics, and reference laboratories.
Key payers referenced in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical context for measuring itraconazole, the typical sites of service where testing occurs, and the common modifiers associated with lab billing. The publication outlines benchmarks and reimbursement context where available, summarizes relevant coding considerations for billing teams, and highlights policy updates that affect laboratory coverage and payment for therapeutic drug monitoring. Clinical labs, billing specialists, and pharmacy teams will gain practical context on when CPT code 80189 is used and what to expect in payer coverage patterns and documentation expectations.
Data not available in the input: associated taxonomies, ICD-10 diagnoses, related codes, and detailed payer-specific reimbursement rates.
Billing Code Overview
CPT code 80189 describes a laboratory test in which a lab analyst performs the technical procedures required to quantify the level of itraconazole, an antifungal medication, in a patient specimen such as serum. This measurement is used to assess drug exposure, guide therapeutic drug monitoring, and detect subtherapeutic or potentially toxic levels in patients receiving itraconazole therapy.
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Service type: Therapeutic drug monitoring / quantitative antifungal assay
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Typical site of service: Hospital clinical laboratory, independent reference laboratory, or outpatient laboratory draw site
Clinical & Coding Specifications
Clinical Context
A patient receiving itraconazole therapy for systemic or invasive fungal infection undergoes therapeutic drug monitoring. Typical patients include those treated for histoplasmosis, blastomycosis, aspergillosis, or prophylaxis in immunocompromised hosts (for example, organ transplant recipients or patients with hematologic malignancy). A clinician orders a serum itraconazole level when there is concern for subtherapeutic exposure, potential toxicity, unexpected treatment failure, drug-drug interactions (notably with strong CYP3A4 inhibitors or inducers), or poor adherence.
Workflow: A clinician documents indication and timing for trough sampling in the medical record and orders the test. A phlebotomist collects a serum specimen at the specified time relative to dose. The specimen is sent to the clinical laboratory. A laboratory analyst performs the quantitative itraconazole assay (e.g., LC-MS/MS or validated immunoassay) and reports the numerical concentration and interpretive comment to the ordering provider. The provider reviews the result and adjusts dosing or investigates interactions accordingly.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the professional interpretation component if applicable to lab testing arrangements. |
52 | Reduced services | Use when the test is partially performed or limited relative to full procedure.