HCPCS code P9604 – Laboratory Specimen Collection Travel

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Key takeaways

HCPCS code P9604 is the flat-rate travel allowance for medically necessary laboratory specimen collection from a homebound or nursing home bound patient.

P9603 and P9604 open with the same one-way descriptor, so direction is not what separates them. The separator is the payment basis: P9603 pays per eligible mile, P9604 pays a flat, prorated trip charge.

Use P9604 when the trained technician travels 20 eligible miles or less to and from one location. Longer round trips, and trips to more than one location, belong on P9603.

For CY 2026 the flat rate is $12.50 per trip and the per-mile rate is $1.25. Both amounts are prorated across the Medicare patients whose specimen collection fee is payable.

A travel allowance is payable only when a specimen collection fee is payable for that patient, so the collection code carries the travel claim.

Practice management software like Pabau keeps homebound documentation, mileage records, and claim status on one patient record. Lab billing teams can then evidence a trip months later.

HCPCS code P9604: definition and code details

HCPCS code P9604 is the Medicare travel allowance code billed on a flat-rate basis. Its official descriptor covers one-way travel for medically necessary laboratory specimen collection from a homebound or nursing home bound patient. The descriptor then ends with the words prorated trip charge.

The code sits in the HCPCS Level II P-series, which covers pathology and laboratory services. Payment comes under the Clinical Laboratory Fee Schedule (CLFS).

Which basis applies is decided by the trip itself, not by the laboratory. CMS sets the rule in the Medicare Claims Processing Manual, Chapter 16, section 60.2, as revised for CY 2026 by Change Request 14345.

What P9604 covers and what it does not

P9604 covers the transportation and personnel cost of sending a trained technician out to collect a specimen. Three conditions have to hold before the code is payable at all.

• A specimen collection fee is payable for that patient. The travel allowance rides on the collection fee. If no collection fee is due, no travel allowance is due either.
• The patient is homebound or a non-hospital inpatient. CMS points to the homebound description at 42 CFR 424.22(a)(1)(ii), and a patient does not have to be bedridden to qualify. For facility patients, the allowance applies only when no qualified staff are on duty to draw the specimen.
• A trained technician personally drew the specimen. The term covers phlebotomists and does not set an education requirement. A courier who only picks up a specimen someone else drew earns neither fee.

Eligible miles start at the laboratory, or wherever the technician’s collection travel begins, and end where that travel ends. Miles driven for any other purpose are excluded, including miles to a non-Medicare patient and miles to a stop where no specimen was collected. Since January 1, 2022, laboratories may keep that mileage evidence electronically.

Four situations fall outside the code.

• A draw performed at a drawing station or in an office.
• A home visit arranged for convenience rather than medical necessity.
• A specimen pickup that needs only a messenger.
• Travel billed by the ordering physician instead of the collecting laboratory.

P9604 vs P9603: flat rate or per mile

The choice between P9603 and P9604 is a choice of payment basis, not a choice of direction. A widely repeated version of this rule calls P9603 the round-trip code and P9604 the one-way code.

Two units of P9604 are then said to stand in for one unit of P9603. That framing does not survive a reading of either descriptor, because both of them say “one way”.

CMS decides the basis from two facts about the trip. Those are how many eligible miles it ran, and how many locations the technician visited. Working through them in that order settles the code before the claim is built.

Worked example: the flat-rate basis

CMS works this example in the CY 2026 manual revision. A technician drives 7 miles from the laboratory to a nursing home and collects specimens there. The same 7 miles are driven back, with no other stops. Five patients are seen, but a collection fee is payable for only three of them.

The trip ran 14 eligible miles to and from one location, so the flat-rate basis applies. The laboratory divides the $12.50 flat rate by those three patients, which gives $4.17 each. It then submits one claim per patient under P9604, alongside each patient’s collection fee.

Worked example: the per-mile basis

CMS works a matching example on the per-mile side. A technician drives 45 miles from a city laboratory to a rural skilled nursing facility. Blood is drawn from six Medicare patients, and the technician drives the same 45 miles back.

The round trip to one location comes to 90 eligible miles, which is more than 20, so the per-mile basis applies.

Ninety eligible miles at $1.25 gives $112.50 for the trip. Divided across six patients, each claim carries $18.75 under P9603. Notice that the whole round trip is paid inside one code, because the return miles are eligible miles.

Medicare reimbursement rates for CY 2026

Travel allowance amounts are national, and CMS updates them every January through its change request process. The CY 2026 figures come from CR 14345, published as MLN Matters article MM14345 and implemented by transmittal R13576CP, effective January 1, 2026.

Two further points shape what a laboratory can expect to collect on these codes.

• Only Medicare patients enter the calculation. Non-Medicare stops are left out of the eligible miles, and those patients are left out of the divisor when the amount is prorated.
• P9603 is billed to the tenth of a mile. For dates of service from April 1, 2026, CR 14130 has MACs accept decimal mileage. Trips under 100 eligible miles round up to the nearest tenth, and trips of 100 miles or more round to a whole number.

For a laboratory running several home-draw routes a day, the travel allowance is small per claim but constant in volume. Modeling it alongside collection volume is what turns a stack of $4.17 lines into a number worth forecasting.

Which patients qualify for a travel allowance

Eligibility rests on the patient’s situation, not on preference. Medicare pays the collection fee and the travel allowance when a trained technician must go to the patient. That applies where the patient is homebound, or is an inpatient somewhere other than a hospital.

CMS describes homebound by reference to 42 CFR 424.22(a)(1)(ii), and notes that a patient need not be bedridden to meet it.

• Homebound patients. Leaving home takes a considerable and taxing effort because of illness or injury. Severe COPD on supplemental oxygen, end-stage renal disease, post-surgical immobility, and advanced dementia are common examples.
• Non-hospital inpatients. A patient in a skilled nursing facility or similar setting qualifies only where no qualified personnel are on duty to collect the specimen.
• Who does not qualify. A patient who is not confined to the facility falls outside the benefit. So does a facility with staff available to draw, and a visit arranged for convenience.

The specimen type matters as much as the patient. A collection fee is payable for blood drawn by venipuncture and for urine collected by catheterization. It is not payable for specimens whose collection cost is minimal, such as a throat culture or a routine capillary puncture.

Confirming the specimen type and the setting before dispatch saves a claim that would otherwise be denied.

How to bill HCPCS code P9604: step by step

Billing this code correctly is mostly a matter of recording the trip while it happens. The steps below follow one visit from order to submission.

1. Confirm the patient qualifies. Obtain the order and the clinical documentation showing the patient is homebound or a non-hospital inpatient. The record should also show that the collection is medically necessary on this date.
2. Confirm a collection fee is payable. Blood by venipuncture and urine by catheterization qualify. Only one collection fee is allowed per patient encounter, however many specimens are drawn.
3. Log the trip as it runs. Record the date, each address visited, whether a specimen was collected there, and the mileage. Electronic mileage records are acceptable and must be shareable with your MAC.
4. Total the eligible miles. Count the miles to each location where a Medicare patient received collection services, plus the miles back to the laboratory. Leave out any detour made for another purpose.
5. Pick the basis from that total. Twenty eligible miles or less to and from one location is P9604. More than 20 eligible miles, or more than one location, is P9603.
6. Prorate the amount. Divide $12.50 by the number of Medicare patients at that location whose collection fee is payable. That quotient is the travel allowance on each of their claims.
7. Submit one claim per patient. Each claim carries P9604, the collection code such as CPT code 36415 or G0471, and the test itself. The laboratory that drew the specimen is the entity that bills.

Codes G0471, P9612, and P9615 also describe specimen collection, so the code on the claim depends on the setting and the method. Whichever one applies, it is the collection fee that makes the travel allowance payable, which is why the two lines are prepared together.

Required documentation for P9604 claims

Travel allowance claims are small, repetitive, and easy to review in bulk, which is what makes the trip record worth keeping properly. Four elements carry most of the weight in a review.

• The physician order. A signed order for the test, with documentation of the patient’s homebound or inpatient status and why a visit is needed.
• Medical necessity on each date. A standing order on its own rarely satisfies a reviewer. Each date of service should have documentation showing the patient still met the criteria.
• The trip log. Date, addresses, whether a specimen was drawn at each stop, mileage, and the technician who traveled. This is the evidence that supports both the basis you chose and the proration.
• The proration worksheet. Keep the count of patients used as the divisor for that trip. Without it, a reviewer cannot reconcile the amount billed on any single claim.

These records answer the two questions a reviewer asks about a travel allowance: was a collection fee payable, and was the right basis used. Holding them in the billing record rather than in a courier spreadsheet is what keeps a year of routes reviewable.

Common claim denial reasons and how to avoid them

Denials on these lines cluster around a short list of causes, most tracing back to the trip record rather than the code. The denial codes guide maps each remittance message onto the cause below.

Where MAC policy still matters

The amounts and the choice of basis are national, and no contractor sets its own travel allowance rate for CY 2026. What varies is the claim handling around them. Each MAC sets how it wants mileage evidence submitted, which billing articles it publishes, and what its reviewers examine after payment.

The manual text in force before 2026 asked claimants to identify round-trip travel with modifier LR. Some contractor billing articles still carry that instruction.

A laboratory that crosses jurisdictions should keep one page per MAC. Record the billing article, the date it was read, and the claim conventions it asks for. Claims go to the MAC for the jurisdiction where the patient is, which matters most when routes run across a state line.

Private payer coverage for P9604

P9604 is a Medicare construct, and commercial payers are not bound to it. Some plans recognize the code and pay their own amount. Others fold travel into the collection fee, and some do not cover home collection at all. Medicaid managed care plans vary in the same way.

• Verify before the first trip. Ask the plan whether P9604 is payable, at what amount, and what documentation it wants. A single call saves a quarter of rework.
• Do not assume Medicare criteria carry over. A plan may define homebound differently, may not prorate at all, or may require prior authorization for home collection.
• Medicare Advantage. These plans cover Medicare-covered services, so the travel allowance is in scope when the criteria are met. Claim submission rules still follow the plan, not the MAC.

Reconciling remittances across Medicare and commercial payers is what surfaces these differences quickly. Posting every remittance to the same patient record shows which payers pay the travel line, which bundle it, and which deny it every time.

Keeping travel allowance claims audit-ready with Pabau

Most laboratories reconstruct these trips after the fact. The mileage sits with the courier, the homebound note sits in the patient chart, and the proration count sits in someone’s head. When a reviewer asks about a $4.17 line from eighteen months ago, assembling the answer costs more than the claim ever paid.

Practice management software like Pabau keeps the visit, the documentation, and the billing record on the same patient file. The order, the homebound note, the visit date, and the codes submitted all sit together. The evidence for a travel allowance line is assembled while the visit is fresh, not months later.

Pabau’s software for billing teams then tracks what was submitted and what came back. Repeated denials on travel lines surface as one trend, instead of as scattered small write-offs. For teams working across several locations, that is the difference between fixing a basis error once and repeating it for a year.

Keep lab billing evidence where the visit happens

Pabau keeps orders, clinical documentation, and billing records on one patient file. Travel allowance and specimen collection claims can then be evidenced long after the trip. See how it works for your laboratory.

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Conclusion

P9604 pays a flat, prorated trip charge for medically necessary specimen collection travel, and P9603 pays for the eligible miles driven. Neither code is the round-trip version of the other. The trip itself decides which one applies.

Twenty eligible miles or less, to and from one location, is the flat-rate basis. A longer round trip, or a route with more than one stop, is the per-mile basis.

Get the mileage, the location count, and the patient count onto the visit record, and the rest of the claim follows from them.

The CY 2026 amounts are $12.50 per flat-rate trip and $1.25 per eligible mile, both prorated and both updated each January. To see how Pabau keeps that evidence attached to the visit it came from, book a demo.

Continue your research

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