Specialty
Infectious disease billing services
Infectious disease billing services follow the physician from the hospital floor to the infusion chair.
See where claims are getting stuck. No patient data needed.
Inpatient consults go to Medicare as initial or subsequent hospital care, because Medicare does not recognize the consultation codes, and a group gets one hospital visit per patient per day for each specialty. In the office, infusions take one initial code per encounter, drugs from single-dose vials carry JW or JZ, and HIV prevention runs on its own Medicare codes with no cost sharing. Remitwright gives infectious disease practices a dedicated biller who applies those rules visit by visit and works denials back to the cause.
Infectious disease billing is one of Remitwright's specialty billing services, each set out with its own code families, denial reasons and payer rules.
Last reviewed by the Remitwright billing team. Editorial policy
- 96365-96368
- 99202-99215
- 99221-99223
Denials
Why infectious disease claims get denied
The reasons that come up most on infectious disease remittances, with the usual cause and the fix. Code explanations are our own; the official list is maintained by X12.
| Code | Reason | Usual cause | The fix |
|---|---|---|---|
| CO-97 | Second hospital visit on one day | Two physicians of the same specialty in the same group each billed a hospital visit for one patient on one date, or a covering partner billed the evening round | One per diem code per patient per day for the group, billed by one physician at the level the day's combined notes support |
| CO-234 | Extra initial administration code | Two initial infusion codes billed through one access site, including both lumens of one catheter, or 99211 billed with the infusion | Administration hierarchy set in charge entry, with a second initial code only for a documented separate access site |
| CO-4 | Drug line missing its modifier | An antibiotic from a single-dose vial billed with neither JW nor JZ, or FS placed on an office visit | Vial type and wasted amount captured with the administration record, and FS kept to facility visits |
| CO-11 | PrEP code without the PrEP diagnosis | Counseling or a PrEP drug billed without Z29.81, or a drug used to treat HIV billed under a PrEP code | PrEP visits tagged at scheduling, with HIV treatment kept on its own codes and its own drug benefit |
| CO-119 | Over the yearly PrEP limit | A ninth PrEP counseling visit or a ninth HIV screening inside 12 months | Running count of counseling visits and screenings per patient checked before each claim |
| CO-197 | No approval on file | An outpatient infusion or a specialty drug given before a Medicare Advantage or commercial plan that requires approval had granted it | Plan policy checked at referral and the approval number carried to the claim |
Codes
Common infectious disease codes and modifiers
Code families by number with our own one-line explanations. CPT descriptors belong to the AMA and are not reproduced here.
| Codes | What the family covers |
|---|---|
| 96365-96368, 96374 | Intravenous infusion and push for antibiotics given in the office. One initial code per encounter unless separate access sites are medically necessary, with sequential and concurrent add-ons after it. |
| 99202-99215, G2211 | Office visits for long-running infections such as HIV and hepatitis, with the G2211 add-on when the physician carries the patient's ongoing care for one serious or complex condition. Medicare does not limit G2211 by specialty. |
| 99221-99223 | Initial hospital inpatient or observation care. A consulting infectious disease physician uses these for the first visit of the stay, in place of the consultation codes Medicare does not pay, when the note meets the code's requirements. |
| 99231-99233 | Subsequent hospital care, a per diem service: one visit a day for the physician and any partner of the same specialty in the same group, leveled on decision making or time. |
| G0011, G0012, G0013 | HIV preexposure prophylaxis: counseling by the physician or another qualified professional, counseling by clinical staff, and giving an injectable PrEP drug. |
| G0316 | Prolonged inpatient or observation time, reported only when time sets the visit level and the day's total reaches the Medicare threshold, 15 minutes past the base code's time: 90 minutes with 99223, 65 minutes with 99233. |
| J0738, J0739, J0750-J0752, J0799 | The PrEP drugs themselves: two injectables, three oral products, and a catch-all code for any other FDA-approved PrEP drug. |
Modifiers that matter
- 25
- A significant, separately identifiable office visit on the same day as an infusion or injection. 99211 is never billed with drug administration, because its work is already built into those codes.
- JW and JZ
- Drugs from single-dose vials or packages: JW on its own line for the amount thrown away, JZ when nothing was discarded. Neither goes on a drug from a multi-dose vial.
- FS
- A split or shared hospital visit, billed by whichever of the physician or nonphysician practitioner did more than half the total time or the substantive part of decision making. Office visits cannot be split or shared.
- AI
- Left off. Only the principal physician of record adds it to initial hospital care; a consulting infectious disease physician bills the same initial codes without it.
Hospital consults without consultation codes
Medicare stopped paying the consultation codes in 2010. When a hospitalist asks an infectious disease physician to see a patient, the first visit of the stay is billed as initial hospital care, 99221-99223, if the note meets that code's requirements, and the days after as subsequent care. Medicare also accepts a subsequent care code for a first visit when the record supports that level, and the AI modifier stays with the physician who oversees the admission.
Medicare Advantage, Medicaid and commercial plans set their own policy on consultation codes, so the same note can be coded two ways depending on who pays. Your biller keeps that rule for each plan and applies it at charge entry; the medical coding service covers how visit levels are set from the note.1
Payers
Payer notes
- MedicareThe consultation codes have not been recognized for Part B payment since January 1, 2010. In the hospital and the nursing facility, physicians bill the initial or subsequent care code that fits the work, and Medicare accepts a subsequent care code for a first visit when the record supports that level. Unlisted code 99499 means records and manual review before payment.1
- MedicareMACs pay one hospital visit per day per physician for the same patient. A covering physician's second visit that day is not paid. Physicians in different specialties are both paid when each manages a different part of the care and the visits carry different diagnoses.1
- MedicareA hospital visit counts as initial only when neither the physician nor a partner of the same specialty in the same group has furnished any professional service during the stay; after that, every visit is subsequent care.1
- Medicare and NCCIPhysicians report drug administration codes for services in their offices, not in a hospital outpatient department or emergency department, where the hospital reports them. Only one initial service code is reported per encounter unless separate access sites are medically necessary.2
- MedicareJW reports discarded amounts from single-dose containers or single-use packages separately payable under Part B, on a line next to the administered amount. JZ is required on those drug claims when nothing was discarded.3
- MedicareCMS's JW and JZ FAQ says neither modifier is used for drugs from multiple-dose containers.5
- MedicareSince September 30, 2024, Part B covers HIV PrEP drugs, their administration and supply, up to 8 counseling visits and 8 HIV screenings every 12 months, and one hepatitis B screening, with no deductible or coinsurance. Part D still covers the same drugs when they treat HIV.4
Authorizations
Original Medicare has no prior authorization step for an inpatient infectious disease visit or most office infusions. Its limits work on the claim instead: the per diem rule, NCCI edits and drug coverage policy. Medicare Advantage and commercial plans decide for themselves whether an outpatient infusion or a specialty drug needs approval, and whether they still pay the consultation codes Medicare dropped. Your biller reads each plan's policy at referral, records the approval with the order and codes hospital consults to each plan's rule.
Documentation traps
- A hospital note that does not show which partner saw the patient that day, so two visits look like one group billing twice
- Total time for a long inpatient day recorded without detail, when G0316 depends on it
- Infusion start and stop times missing, so initial, sequential and concurrent codes cannot be told apart
- No wasted amount recorded for a single-dose vial, leaving the JW line unsupported
- A PrEP visit charted like an HIV treatment visit, with the prevention diagnosis left off
What a specialist checks
Specialist or generalist for infectious disease billing?
A generalist biller can enter an infectious disease claim. Whether it pays turns on three things specific to infectious disease billing, and a specialty-aware biller checks each one.
Code families
Each family billed with what the chart has to show for it.
- 96365-96368, 96374
- 99202-99215, G2211
- 99221-99223
Modifiers
Applied only where the note supports them, line by line.
- 25
- JW and JZ
- FS
If you are moving from another billing company or an in-house biller, switching billing companies follows a plan: the old and new processes run side by side until the new one is proven, and every login and every infectious disease claim stays in your name.
What we handle
What we handle for infectious disease practices
- Medical codingCPT, ICD-10 and modifiers assigned correctly
- Charge entryEvery encounter captured, nothing left unbilled
- Medicare billingPart B claims, MSP, ABNs and appeals
- Prior authorizationAuths requested, tracked, attached to claims
- Denial managementEvery denial read, worked and appealed
- A/R follow-upUnpaid claims chased before filing limits
A dedicated biller with named cover, working inside your system and reporting to you on one written page. How it works sets out the five stages.
Worked example: two partners, one patient, one day
An infectious disease group follows a hospital inpatient with an infected joint replacement. One physician sees the patient in the morning and bills 99232. That evening her partner returns after new culture results come back and bills 99232 as well. The second claim is denied, because both physicians share a specialty and a group and Medicare pays one hospital visit per day.
The biller confirms with the group which physician bills the day and replaces the two lines with one subsequent care code at the level the combined morning and evening notes support. The group's rounding sheet now lists every partner who saw a patient each day, so each day is coded once before anything goes out.
Software
Systems infectious disease practices usually run
Your biller works inside your system as a user you create. All the systems we work in.
Questions
Questions about infectious disease billing
How do we bill an inpatient consult to Medicare?
Can two partners bill on the same hospital day?
When can we bill prolonged time in the hospital?
How are office antibiotic infusions coded?
When do we use JW and JZ?
How is HIV PrEP billed to Medicare?
Can an infectious disease physician bill G2211?
What does an infectious disease practice provide so billing can start?
Next step
See where your infectious disease claims are getting stuck.
Three quick questions. No patient data. A billing specialist reads every request and replies in writing.
- Three questions, about two minutes
- No patient data, no software to buy
- A written reply from a biller, not a sales deck
You answer three questions
A billing specialist reads them
A written reply by email
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- A billing specialist reads your answers and replies by email.
- If a look at real claims makes sense, we agree read-only access under a BAA first.
- You get a written summary of what is worth working and what it would take. No commitment.
While you wait: see the sample weekly report or read how switching works. You can also download the sample weekly report (PDF).