CPT-4 Code 99355 To report additional prolonged outpatient E&M services, CPT-4 code 99355 (each additional 30 minutes) must be billed in conjunction with code 99354.

Billing Calculations CPT-4 codes 99354 and 99355 are subject to the least restrictive frequency limitation as the required companion code. To calculate the amount of time that is payable for prolonged outpatient services, take the total face-to-face time and subtract the time of the primary E&M service. The following table may be used to calculate billing for prolonged outpatient E&M services.

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Time of E&M visit code not included First hour Each additional 30 minutes

Less than 30 minutes Not reported Not reported

30 – 74 minutes 99354 Not reported

75 – 104 minutes 99354 99355

105 – 134 minutes 99354 99355 (quantity of 2)

135 – 164 minutes 99354 99355 (quantity of 3)

165 – 194 minutes 99354 99355 (quantity of 4)

Inpatient ServicesCPT-4 Code 99356 – To report prolonged inpatient E&M services, CPT-4 codes 99356 (inpatient setting; first hour) must be billed in conjunction with one of the following E&M service codes:

Description & CPT-4 Code

Initial hospital care and subsequent hospital care

99221 – 99223
99231 – 99233

Inpatient consultation
99251 – 99255

Nursing facility services
99304 – 99310

Inpatient psychotherapy with E&M component
90822, 90829