Cognitive work in the hospital and the clinic
Infectious disease (ID) physicians earn most of their revenue from evaluation and management — hospital consultations for complex infections, follow-up visits, and long-term outpatient care for HIV, hepatitis and chronic infections. There are few procedures, so visit levels, diagnosis specificity and capturing every hospital encounter matter more than in most specialties. ID clinics may also run infusion services and manage expensive drugs that need approvals.
Hospital consultations and visit levels
| Situation | How it is billed |
|---|---|
| Inpatient or observation consult, Medicare | Initial hospital care codes (99221–99223); consultation codes are not paid |
| Inpatient consult, payers that pay consult codes | 99252–99255, with the request and the reason documented |
| Follow-up hospital visits | 99231–99233 by medical decision-making or total time |
| Office consultations | 99242–99245 where paid; otherwise office E/M codes |
ID decision-making often involves reviewing cultures, imaging and drug levels, discussing management with other physicians and managing drugs that need monitoring for toxicity, which supports higher levels when documented. Diagnoses should name the organism, site and resistance where known — specificity that also matters to hospital quality programs.
Outpatient antibiotics, HIV care and prevention
- Outpatient parenteral antibiotic therapy (OPAT): infusions given in the clinic are billed with infusion administration codes and drug units; home infusion is billed by the home infusion pharmacy, while the physician bills visits and the work of monitoring labs and adjusting therapy as E/M or care management where it qualifies.
- HIV care: antiretroviral drugs are usually covered through pharmacy benefits with prior authorization; long-acting injectable treatment given in the clinic is billed with the drug and administration codes.
- PrEP: since September 2024, Medicare Part B covers HIV pre-exposure prophylaxis drugs, related HIV and hepatitis B screening, and up to eight counseling visits a year, without deductible or coinsurance.
- Vaccines and travel medicine: covered vaccines are billed with product and administration codes; travel consultations and travel vaccines are often not covered and are collected from the patient with notice.
Approvals and payer rules
Hepatitis C treatments, HIV medications, long-acting injectables and some antibiotics require prior authorization, often with lab results attached. Telehealth is common for ID follow-up, with payer-specific rules. See prior authorization services.