How to bill 15-minute units: T1019, S5125, S5130 and rounding

Most Medicaid home and community-based services are paid in units of time, and the most common unit is 15 minutes. That sounds simple until a visit runs 52 minutes, or a client has three short visits in a day, or the authorization runs out mid-month. This guide covers what a unit is, the codes you will see most, how rounding changes what you can bill, and how to keep units inside the authorization.

Payers set their own rules. Everything below is general: check your state Medicaid provider manual, your managed care contracts and your billing adviser before you change how you bill.

What a unit of service is

A unit is the block of time a payer pays for. The procedure code tells you the service and, usually, the unit: "per 15 minutes", "per hour", "per diem" or "per visit". The payer's fee schedule gives the rate per unit. If personal care pays $6.50 per 15-minute unit, a full hour is 4 units, or $26.00.

Common codes in home care

These HCPCS codes are widely used for home and community-based services. Descriptions are summarized; states often add modifiers and their own definitions, so check your fee schedule.

Code	Service (summary)	Usual unit
T1019	Personal care services	15 minutes
S5125	Attendant care services	15 minutes
S5130	Homemaker services	15 minutes
S5135	Companion services, adult	15 minutes
S5150	Respite care, unskilled	15 minutes
T1030 / T1031	Nursing care in the home (RN / LPN)	Per diem in many states

The difference between T1019 and S5125 is a frequent question. In many states T1019 is used for state plan personal care and S5125 for attendant care under a waiver program, but the split varies. Use the code your state assigns to the program and service on the authorization.

Rounding rules

A visit rarely lasts an exact number of units. The payer's rounding rule decides what happens to the leftover minutes. You will see four rules.

The 8-minute threshold

Bill a unit for each full 15 minutes, plus one more if the remainder is 8 minutes or more. So 0 to 7 minutes is 0 units, 8 to 22 is 1, 23 to 37 is 2, 38 to 52 is 3, and 53 to 67 is 4. A 52-minute visit is 3 units; a 53-minute visit is 4.

Nearest whole unit

Divide minutes by the unit size and round to the nearest whole number. For whole minutes and 15-minute units this gives the same answer as the 8-minute threshold. With other unit sizes, or with seconds counted, it can differ.

Whole units only

Only complete units are billed. A 52-minute visit is 3 units, a 29-minute visit is 1. This is the most conservative rule and the easiest to defend.

Any part counts

Any part of a unit is billed as a full unit. A 16-minute visit would be 2 units. Few public payers allow this; do not use it unless your contract says so in writing.

Per visit or per day

Some payers round each visit; others ask you to add up the minutes for the same client, service and day and round once. The difference matters with short visits. Two 7-minute medication reminders are 0 units each when rounded per visit, but 14 minutes in the day is 1 unit when added first. Read the billing section of your provider manual for "cumulative" or "per date of service".

A worked example

Three visits for one client in a week, all T1019 at an example rate of $6.50 per unit, 8-minute threshold, rounded per visit:

Visit	Verified minutes	Units	Amount
Monday	67	4 (60 + 7, remainder under 8)	$26.00
Wednesday	52	3 (45 + 7)	$19.50
Friday	98	7 (90 + 8)	$45.50
Total	217	14	$91.00

Try your own visits in the free 15-minute unit calculator, which shows every rule side by side.

Bill from verified time, not the schedule

In states that match claims to EVV records, units on the claim must be supported by the verified clock in and clock out. If a visit was scheduled for two hours but verified at 1 hour 40 minutes, bill 7 units (100 minutes), not 8. Billing the scheduled time is the fastest way to denials and, at worst, recoupment after an audit.

Where the office corrects a visit, for example a forgotten clock out, the correction should carry a reason code and the units should come from the corrected, documented time.

Stay inside the authorization

Most Medicaid services need a prior authorization: a number of units of a service, for one client, between two dates, sometimes with a weekly or monthly limit as well. Units over the limit, or after the end date, are generally not paid.

• Check at booking. When you schedule a visit, check that the authorization covers it. A visit that will go over should be raised before it happens.
• Track the burn rate. Compare units used with time passed. If 60% of the units are gone at 40% of the period, the authorization will run out early. The free authorization unit tracker shows the projected run-out date.
• Renew early. Start the reauthorization well before the end date. Gaps between authorizations are a common cause of unpaid visits.
• Watch underuse too. Using far fewer units than authorized can mean the client is not getting the care in their plan, which payers and case managers notice.

Before you submit

1. Every visit verified, or corrected with a reason code.
2. Units calculated with the payer's rule from verified minutes.
3. Procedure code and modifiers match the authorization.
4. Dates of service fall inside the authorization period.
5. Total units do not exceed the authorization, per week, month or in total.
6. Rendering worker and client IDs present where the payer needs them.

And check what you earn on each unit with the bill rate vs pay rate margin calculator: a rate that looks fine per unit can leave little once overtime, payroll taxes and travel are counted.