Infectious disease billing covers HIV chronic care, outpatient IV antimicrobial infusions, complex consultations, and high-cost antibiotic/antifungal J-codes—each with its own payer rules and documentation requirements. VeriMedix brings dedicated ID billing expertise to maximize reimbursement and minimize denials.
Infectious disease (ID) practices face a billing landscape defined by high-acuity consultations, chronic HIV/AIDS management, and an expanding outpatient parenteral antimicrobial therapy (OPAT) program where IV antibiotics, antifungals, and antivirals are administered in office, home infusion, or infusion center settings. Consultation billing—both initial (99242–99245 for office, 99251–99255 for inpatient) and follow-up (99231–99233 for hospital subsequent visits)—requires that the requesting provider's name and reason for consultation are documented, a written opinion or advice is rendered, and the report is communicated back to the requesting provider. Medicare no longer pays separately for consult codes from the consulting physician's perspective (they use 99202–99215 for new/established patients instead), so correct new vs. established patient classification is essential for accurate reimbursement in Medicare patients.
HIV management generates recurring revenue through quarterly E/M visits (99213–99215 based on MDM complexity with multiple chronic conditions and prescription drug management), laboratory monitoring (CD4 count 86359, HIV viral load 87536), and increasingly, pre-exposure prophylaxis (PrEP) counseling and management. ICD-10-CM coding for HIV must distinguish between asymptomatic HIV infection (Z21), symptomatic HIV disease (B20), and HIV disease with specific manifestations (B20 + a secondary code for the manifestation, e.g., B20 with C46.9 for Kaposi's sarcoma). Antiretroviral medication management—documented through prescription monitoring, drug interaction review, and adherence counseling—supports moderate-to-high MDM complexity levels. Care management codes (99490, 99487, 99489 for chronic care management; 99495–99496 for transitional care management) are particularly applicable for HIV patients with multiple comorbidities transitioning from hospital to outpatient care.
OPAT billing uses the therapeutic infusion hierarchy (96365–96368) for office-administered IV antibiotics, antifungals, and antivirals. High-cost IV antimicrobials have dedicated HCPCS J-codes: daptomycin (J0878), ertapenem (J0992), linezolid (J2185), amphotericin B liposomal (J0289), micafungin (J2248), and others. NDC reporting and JW/JZ modifier compliance (effective 2023 for Medicare single-dose drugs) apply. Prior authorization is required by most payers for high-cost IV antimicrobials and for extended OPAT courses. Infectious disease specialists also play a central role in antimicrobial stewardship, and billing for infectious disease telephone or electronic consultations (99446–99449, 99451–99452 interprofessional telephone/internet consultations) provides an often-overlooked revenue stream for ID specialists who provide expertise to primary care physicians managing complex infections.
Below are commonly billed codes our certified coders manage for infectious disease practices. Always confirm payer-specific coverage and current code values.
| Code | Description | Billing note |
|---|---|---|
99245 | Office consultation, new or established patient; high complexity (for non-Medicare payers) | Requires documentation of request, examination, opinion, and report back to requesting provider; Medicare uses 99215 instead |
99215 | Office/outpatient E/M, established patient, high complexity MDM | Primary level for complex HIV/AIDS follow-up or OPAT management visits on Medicare |
87536 | Infectious agent detection by nucleic acid; HIV-1, quantitative (viral load) | Ordered frequently; billed by performing lab; ID practice bills ordering E/M and any in-house rapid tests |
86359 | T cells (T lymphocytes), total count | CD4 count for HIV monitoring; usually billed by reference lab; confirm if in-house lab performs |
96365 | IV infusion, therapeutic/prophylactic/diagnostic; initial, up to 1 hour | Used for OPAT IV antibiotics in office; document drug, dose, start/stop times |
J0878 | Injection, daptomycin, 1 mg | MRSA/VRE treatment; NDC required; JW/JZ for Medicare; prior auth typically required |
J0289 | Injection, amphotericin B liposome, 10 mg | Invasive fungal infections; high-cost; document organism, culture results, and treatment indication |
99451 | Interprofessional telephone/internet assessment and management, first 5–10 minutes (consultant) | ID specialist provides consultation to another physician by phone/EHR; separately billable; document time and advice given |
99490 | Chronic care management, at least 20 minutes of clinical staff time per calendar month | Billable for HIV/AIDS, hepatitis C, and other chronic infections with two or more chronic conditions; requires care plan |
Our standard operating procedures for infectious disease revenue cycle management — the step-by-step workflow we follow on every claim:
These are the issues we see most often in infectious disease billing — and exactly how we resolve them:
Medicare eliminated separate consult codes; ID specialists must correctly classify new vs. established patients (new = not seen by same group/specialty in past 3 years) and bill 99202–99205 or 99212–99215. Using consult codes on Medicare claims causes rejection. Fix: Configure billing system to auto-route consult code orders to 99202–99215 for Medicare; create a payer-specific grid for which plans still honor consult codes.
Extended antibiotic courses (4–6 weeks for endocarditis, osteomyelitis) require re-authorization if coverage spans two benefit periods or exceeds initially authorized days. Fix: Build OPAT tracking log with PA expiration dates; assign a coordinator to request extensions at least 5 business days before expiration with updated clinical notes showing treatment response.
Z21 (asymptomatic HIV) vs. B20 (HIV disease) distinction is critical: B20 is used when the patient has an AIDS-defining illness or is otherwise symptomatic; Z21 for asymptomatic/controlled HIV. Coding B20 incorrectly for asymptomatic patients can affect insurance coverage and create audit risk. Fix: Require physician attestation of HIV status at each visit; configure EHR to prompt for symptomatic vs. asymptomatic status before ICD-10 auto-assignment.
Chronic care management (99490, 99487) is frequently not billed for qualifying HIV and hepatitis C patients despite regular care plan oversight. Fix: Identify all eligible patients with two or more chronic conditions; implement a CCM enrollment workflow with electronic care plan templates; designate clinical staff time tracking for monthly CCM documentation.
In-office rapid tests (e.g., 87804 for rapid influenza, 86308 for rapid monospot) are separately billable when a CLIA-waived lab certificate is on file. Many practices fail to bill these codes. Fix: Conduct a CLIA waiver audit; train front desk and nursing staff to capture all in-office diagnostic tests as separate charge items; verify billing rights for each test code against the practice's CLIA certificate.
Verimedix works inside the systems infectious disease practices already use, including:
Medicare does not recognize CPT consult codes (99251–99255). The consulting ID physician should bill initial hospital care codes (99221–99223) if they are the admitting physician, or subsequent hospital care codes (99231–99233) if the patient is already admitted. The key is accurate documentation of new vs. established patient status and the role of the ID physician in care. Some payers and Medicaid programs still honor 99251–99255—verify by payer.
Bill appropriate E/M codes based on MDM complexity or time (99213–99215 for established patients). ICD-10 Z11.4 (encounter for screening for HIV) or Z20.6 (contact with and exposure to HIV) support medical necessity. In-office HIV rapid test (87389) is separately billable with a CLIA waiver. STI screening labs (87591 for gonorrhea NAAT, 87491 for chlamydia NAAT) are billable per payer coverage policy. Prevention counseling (99401–99402) may be separately payable under some commercial plans.
Include in the clinical record: organism identified, susceptibility testing, rationale for IV therapy over oral (e.g., poor oral bioavailability, failed oral therapy), planned duration and endpoint criteria, monitoring plan for drug levels and organ function, and attending physician's treatment order. Prior authorization submissions should include culture results, imaging, and prior antibiotic course documentation.
Hepatitis C E/M visits (99213–99215) with ICD-10 B19.20 (unspecified viral hepatitis C without hepatic coma) or B18.2 (chronic viral hepatitis C) support standard visit billing. Direct-acting antivirals (e.g., sofosbuvir/velpatasvir, ledipasvir/sofosbuvir) are dispensed by specialty pharmacy and billed under Part D; the practice bills E/M management. Pre-treatment genotyping (87902) and viral load quantification (87522) are separately billable.
Yes—they represent a legitimate and often-missed revenue stream for ID specialists who routinely advise primary care physicians on complex antibiotic decisions. Bill 99451 (consultant's work, first 5–10 minutes) or 99452 (additional 5–10 minutes) per calendar month per patient. The requesting provider bills 99446–99449. Document: patient name, requesting provider, date, time spent, clinical question, and advice given. Some payers restrict to established patients only.
Use standard E/M codes with place of service 02 (telehealth) or 10 (patient's home) and modifier -95 for synchronous audio-video visits. Medicare telehealth flexibilities expanded during the COVID-19 PHE have been extended through at least 2026 in certain contexts; verify current Medicare telehealth policies annually. Document that the patient consented to telehealth and that the visit was audio-visual (not audio-only unless a specific audio-only code is used, such as 99441–99443).
Verimedix handles the entire infectious disease revenue cycle — coding, submission, denials, and A/R — so your team can focus on patients.