What is a billing unit on a NEMT claim?
A billing unit is the quantity on a claim line, entered in box 24G of the CMS-1500. The code defines what one unit is: one trip or leg for base codes such as A0130, one mile for mileage codes such as S0209, one half hour for T2007 waiting time, and one day for lodging and meals. Rounding belongs to the payer, and Medicare, Indiana, and Oregon each round miles differently.
On this page
The code sets what a unit counts
A unit is the count on a claim line, and the HCPCS descriptor tells you what is being counted. Paper claims carry it in box 24G. The NUCC instructions call for a 1 when a single service was performed, and for a decimal point when you report part of a unit.
| What one unit counts | Example codes | How the descriptor or payer puts it |
|---|---|---|
| One trip or leg | A0100, A0130, T2003, T2005 | Colorado lists A0130 and T2005 as “One Way Trip” and counts one unit per leg of a taxi trip |
| One mile | A0425, S0209, S0215, T2049 | “Per mile” or “per statute mile” in the descriptor |
| One half hour | T2007, A0420 | Both descriptors bill waiting time in half-hour increments |
| One day | A0180 to A0210 | Colorado prices lodging and meals per diem, one per day for the member and one per day for each escort |
| One rider | A0120 with TK in Colorado | The unit count equals the number of people carried |
In Texas, TMHP’s 2021 notice on T2003 said each leg pays per authorized seat, so two authorized passengers on one leg earn two leg rates.
Trips, legs, and round trips
The programs here count a one-way trip leg as one unit of the base code, but they lay out round trips differently:
- Colorado: each leg of a taxi trip is a unit, which puts an out-and-back ride at two.
- Indiana: when a member rides out and back on the same day at the same level of service, both legs share one line with two units, and all the miles share one mileage line. Waiting outside a lab mid-route does not create a new trip. A separate trip later that day is billed with the XE modifier.
- North Carolina: a taxi from home to dialysis is one unit. The same taxi back later that day makes the line A0100 with two units. Each date of service gets its own line.
- Medicare ambulance: each trip generally takes two lines, one for the service and one for the miles.
Rounding miles and minutes
| Payer | Mileage rule |
|---|---|
| Medicare ambulance | Below 100 covered miles, report tenths, always rounding up (a trip under a mile starts with 0, as in 0.9). From 100 miles on, report whole miles, rounded up. |
| Indiana | Whole miles, nearest mile wins: a 15.4-mile trip is 15 units and a 15.5-mile trip is 16 |
| Oregon | Any fraction of a mile rounds up |
| South Dakota | Nearest whole mile, no decimals, one mileage allowance per trip |
| Colorado | Whole numbers only |
Time units have rules too. Indiana bills T2007 at one unit per 30 minutes, rounding a remainder of 15 minutes or longer up and a shorter one down. Payment starts after the first half hour, and only if the driver parks outside to wait and the one-way distance reaches 50 miles. Even so, Indiana wants the full wait reported.
Units that draw a second look
High unit counts attract review. Colorado holds any A0425, S0215, or S0209 claim for review once the units pass 52, or 125 for its designated rural counties, and a held claim is denied unless an attachment backs up the trip. Indiana goes the other way on long trips: it waives the 250-unit medically unlikely edit for A0425.
On the electronic 837P, the unit type and the count sit on each service line. Nevada’s transportation encounter guide sets the unit type to UN and reports the count in the service unit count field, decimal included when the count needs one. Our CMS-1500 guide covers the paper form, and NEMT mileage billing covers which loaded miles count.
Units that match the trip record
Every unit should trace back to something on the trip record: a leg completed, a mile driven, a wait timed. HealthRide saves GPS-recorded miles along with the real pickup and drop-off times on each trip, and you can pull the trip log report as a CSV or PDF file, so the counts you bill line up with what happened on the road.
Frequently asked questions
- Does a round trip count as one unit or two?
- Usually two, one per leg, but the layout varies. Colorado counts each leg of a taxi trip as its own unit, which makes an out-and-back ride two. Indiana combines both legs on one line with two units if the level of service is the same, and North Carolina bills a same-day taxi out and back as A0100 with two units. Medicare ambulance claims give each trip its own service and mileage lines.
- Can I bill a fraction of a mile?
- Only where the payer asks for it. Medicare wants ambulance miles to the tenth for trips under 100 covered miles, such as 12.4. Indiana, South Dakota, and Colorado want whole numbers. Indiana rounds to the nearest mile, so 15.4 becomes 15 and 15.5 becomes 16, while Oregon rounds any partial mile up.
- How are waiting time units counted?
- T2007 is billed in half-hour units. Indiana sets the rounding: any remainder of 15 to 29 minutes becomes a full unit, and a remainder under 15 minutes is dropped. A 45-minute wait is therefore 2 units, and so is a 70-minute wait. Indiana pays for waiting only beyond the first half hour, and only when the one-way trip covers at least 50 miles.
- Where do units go on an electronic claim?
- On the 837P, each service line carries a unit type and a count. Nevada's transportation encounter guide, for example, sets the unit type to UN, puts the count in the service unit count field, and keeps the decimal when a count needs one.
