- Anesthesia Modifiers
- Appropriate Usage of Modifier 99
- Assistants at Surgery at Teaching Hospitals
- Bundled Services Missing Appropriate Modifiers at Time of Initial Claim Submission
- Clarification for Billing Services on Fingers and Toes Using Modifiers F1-F9, FA, TI-T9 and TA vs. Modifier 50
- Correct Usage of Modifier 79 for Multiple Procedures
- Co-Surgery/Team Surgery/Assistant Surgery Modifiers
- Modifier 25
- Modifier 33
- Modifier 51
- Modifier 52 Claim Submission Billing Reminder
- Modifier 59 and the Subset Modifiers XE, XP, XS, XU - Specific Modifiers for Distinct Procedural Services
- Modifier 90 Reference to Outside Laboratory
- Modifiers Used in CMS-1500 Claim Reporting
- Modifier Usage
- Proper Billing of Surgical Comanagement (Modifiers 54 and 55)
- Proper Use of Modifiers 59 and 91
- Reminder for Submission of Modifier 22
- Repeat Procedures - Modifiers 76 and 77
Modifier 90: Reference to Outside Laboratory
Modifier 90 is to be used when the billing laboratory refers a specimen to another laboratory for testing. In these cases, the billing laboratory is titled the “referring laboratory” while the laboratory that actually performed the test is the “reference laboratory.”
- Only independent billing clinical laboratories (specialty 69) can bill with the 90 modifier. Sometimes a clinical diagnostic independent laboratory, POS 81, refers a specimen to another laboratory for testing, where a modifier 90 is appended.
- The billing entity must be designated as a specialty 69 in their provider enrollment record within the PECOS.
- Must append modifier 90 to referred laboratory test code
- Item 20 mark "Yes" = outside laboratory
- Purchase price must be reflected under charges
- Complete item 32 with NPI, name and address where test was performed
- Appropriate modifier 90 claims include two different CLIA numbers on electronic claims
- Reflect billing provider information
- Laboratory where services were performed (reference laboratory)
- Electronically bill claims with/without modifier 90 and without modifier 90 separately electronically on the same claim
- If no purchased services, leave item 20 blank
- When the laboratory submits claims, services both performed and referred may be billed on the same electronic claim. Regardless, of the services performed, whenever the 90 modifier is billed on a claim, the following information must be included.
| Information | Loop | Field | Identifier |
|---|---|---|---|
| Billing laboratory CLIA number | 2300 | REF02 | X4 |
| Reference laboratory CLIA number | 2400 | REF02 | F4 |
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Revised 9/28/2023