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CPT® Modifier 90

Official Description

Reference (Outside) Laboratory

When laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.

© Copyright 2026 American Medical Association. All rights reserved.

Short Descr	Reference (Outside) Laboratory
Medium Descr	Reference (Outside) Laboratory

Modifiers

22-99 Level I - CPT Modifiers

22 Increased Procedural Services

23 Unusual Anesthesia

24 Unrelated E&M Same Physician PostOp

25 Significant, Separately Identifiable E&M Same Phy & Day

26 Professional Component

27 Multiple Outpatient Hospital E/M Same Date

32 Mandated Services

33 Preventive Services

47 Anesthesia by Surgeon

50 Bilateral Procedure

51 Multiple Procedures

52 Reduced Services

53 Discontinued Procedure

54 Surgical Care Only

55 Postoperative Management Only

56 Preoperative Management Only

57 Decision for Surgery

58 Staged/Related Proc/Srvc Same Phy PostOp

59 Distinct Procedural Service

62 Two Surgeons

63 Procedure Performed on Infants less than 4 kg

66 Surgical Team

73 Discont. OutPat Hosp/ACS Prior to Anesthesia

74 Discont. OutPat Hosp/ACS After Anesthesia

76 Repeat Procedure or Service by Same Physician

77 Repeat Procedure by Another Physician

78 Unplanned Return to OR Same Phy PostOp

79 Unrelated Proc by Same Phy PostOp

80 Assistant Surgeon

81 Minimum Assistant Surgeon

82 Assistant Surgeon (when qual resident surgeon NA)

90 Reference (Outside) Laboratory

91 Repeat Clinical Diagnostic Laboratory Test

92 Alternative Laboratory Platform Testing

93 Synchronous Telemedicine Service Rendered Via Telephone or Other Real-Time Interactive Audio-Only Te

95 Synchronous Telemedicine Service Rendered Via a Real-Time Interactive Audio and Video Telecommunicat

96 Habilitative Services

97 Rehabilitative Services

99 Multiple Modifiers

Date	Action	Notes
2013-01-01	Changed	Changed Code for 2013

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