Starting an independent ID practice: designing the revenue model before day one

Every other specialty starting an independent practice begins with a procedure list. Infectious disease begins with a harder question: what, exactly, are we selling, and who pays for it?

ID is the specialty most reliant on cognitive work and least served by a payment system built around procedures. That is not a complaint — it is a design constraint, and independent ID practices that succeed are the ones that treat it as such. Private ID practice is demonstrably viable; published accounts of established private ID groups describe compensation well above specialty averages. But it is viable because of how the revenue model is constructed, not in spite of it.

The four revenue streams, priced separately

Most sustainable independent ID practices assemble revenue from four distinct sources. Model each one on its own before you combine them, because they have completely different economics, risk profiles and cash timing.

• Inpatient consultation. The traditional core. Volume-driven, dependent on hospital relationships and referral patterns, and paid on evaluation and management codes — which means documentation and time or medical-decision-making levelling determine a large share of realised revenue.
• Contracted hospital services. Antimicrobial stewardship programme leadership, infection prevention medical directorship, and defined coverage obligations. These are services with genuine institutional value, and they are frequently provided for free by ID physicians who were never taught to price them.
• Outpatient clinic. Follow-up, chronic infection management, HIV care, travel medicine, complex outpatient diagnostics. Lower revenue per encounter than inpatient consultation in many settings, but far more schedulable — which matters enormously for practice stability.
• Infusion and OPAT. The ancillary business. Depending on site of care and ownership, this can carry drug margin, nursing and administration payment, and monitoring revenue. It is also the stream with the most capital requirement, the most operational complexity and the most payer risk.

Why the compensation picture matters to your model

ID consistently ranks among the lowest-compensated medical specialties in national surveys, and ID physicians report among the lowest rates of feeling fairly compensated. Fellowship positions have gone unfilled for years. This is not incidental background — it is the market condition your practice operates in.

Read constructively, it tells you two things. First, ID expertise is genuinely scarce and getting scarcer, which strengthens your position when contracting with institutions that need it. Second, any revenue model that assumes ID will be paid like a procedural specialty on clinical work alone is starting from a false premise.

The independent ID practices that work are not the ones that found a way to bill more for a consult. They are the ones that priced everything they were already giving away.

Sequencing the launch

Before you sign anything

1. Map your referral sources concretely. Which hospitals, which services, which physicians, and what is the realistic consult volume. Not the addressable market — the named sources.
2. Establish which institutional services you will provide and whether they are contracted. Stewardship and infection prevention obligations negotiated after you have already been doing them for free are much harder to price.
3. Decide the OPAT model. Will you refer to home infusion providers, partner with an infusion centre, or build your own suite? This is the single largest fork in your capital plan.
4. Complete payer enrollment before build-out. As in any specialty, credentialing timelines — not construction — usually gate your first collection.

Systems, before the first patient

Choose the practice management and clinical systems on what the revenue cycle needs, not on the demo. In ID that means asking a specific set of questions most vendors are not expecting:

• Can it hold contracted fee schedules, so underpayment on a high-value drug claim is detectable at all?
• Can it track an authorisation with an expiry date, and alert before that date passes mid-course?
• Does it support inventory reconciliation against administered doses, or will that live in a spreadsheet?
• Can it report denials by dollars and by root cause, not just by payer?
• How does it handle infusion administration timing and the documentation the hierarchy requires?

Ask to speak to an ID or infusion practice of your size that has run it for two years, and ask what they would not choose again.

The first year

Expect the clinical revenue to arrive before the ancillary revenue. Infusion and OPAT programmes require the referral relationships, the nursing capacity, the pharmacy arrangements and the payer authorisations to all exist simultaneously, and they rarely mature in the first six months. Model the practice as though clinical revenue alone must cover fixed cost for longer than you expect, and treat the ancillary contribution as upside until it is real.

The structural risks worth naming early

• Payer concentration in the infusion business. Drug-heavy revenue means a single payer policy change or authorisation pattern can move your margin materially.
• Coverage obligations that expand without contract changes. The most common way an ID practice's economics erode is by absorbing more institutional responsibility at a fixed fee.
• Documentation discipline on cognitive billing. Where E/M is the core product, documentation is the product specification. Under-levelling is a real and common revenue leak.

What to do next

If you are modelling a launch, start with the OPAT Course Economics tool to see how sensitive a single course of therapy is to site of care and coverage — it is usually the assumption that most changes the shape of the business plan.