MODIFIER 90 Basics Reference (outside) Laboratory:
When a laboratory process is conducted by someone other than the treatment or reporting physician or another credible health care professional, the process is recognized by incorporating modifier 90 to the usual procedure number. When lab tests for a patient are conducted by an outside or reference laboratory, a physician or clinic will use modifier 90. This modifier indicates that, whereas the physician is reporting the facts of a laboratory test, the actual testing component was a laboratory service. When lab procedures are performed by someone other than the treating or trying to report health professional and the laboratory bills the physician for the service, modifier 90 is used.

Inappropriate Implementation
- Modifier 90 should not be reported with morphological pathology or lab services.
- Never include modifier 90 for the drawing fee (36415)
- Cannot be referred to another lab.
- Payers will only reimburse independent clinical laboratories for services submission with CPT modifier 90. Physicians are not permitted to accept action on behalf of laboratories for tests. Laboratories may submit claims effectively to Payers. The service is billed to the physician.
Guidelines for claim submission
- The procedure is carried out by an outside laboratory unrelated to the treating/reporting physician.
- Most of the time, the lab that provided the service would bill the claim.
- It is feasible for one lab to bill for services provided by another lab.
- referring: sending a specimen to a different laboratory for testing
- A benchmark lab obtains a representative from another lab and needs to perform one or more tests on it.
- Modifier 90 must be appended to the referred laboratory test code.
- Mark ‘Yes’ for Item 20: outside lab.
- Undercharges must represent the purchase price.
- Fill out item 32 with the NPI, name, and address of the location where the procedure was performed.
- Two distinct Clinical Lab Improvement Amendment (CLIA) numbers are used in appropriate modifier 90 claims.
- Incorporate billing provider data Laboratory where services were provided (reference lab)
- Bill claims with and without modifier 90 must be submitted independently.
- If no services were acquired, leave item 20 blank.
MODIFIER 90 Example
A patient comes in for an automatically generated complete blood count. The blood sample is taken by office personnel, and the specimen is sent to a third-party lab for analysis. In this case, 36415 is the suitable coding. Venipuncture for venous blood collection, 85027-90 Complete blood count (CBC), automated (Hgb, Hct, RBC, WBC, and platelet count). Modifier 90 should be added to the CPT code explaining the CBC to imply that, while the provider is reporting the process, it was performed by an outside lab. In such cases, the lab will usually bill the physician’s office for its services, and the office will then bill the patient.
However, the problem comes when the laboratory also needs to submit a claim for the offerings. The dates of service may or may not correspond. The provider may bill for the day the venipuncture was conducted, and the experiment may bill for the day the laboratory tests were processed, potentially avoiding duplicate claim edits. The lab, the doctor, or both may be involved in the scheme.
If there is a genuine contract for the physician to charge the lab, the laboratory company is a mistake because they are being paid twice by both the insurance provider and the physician. If the laboratory is filing a claim because there is no agreement for the physician to charge the lab, then the doctor is a mistake and should not be filing a claim or reimbursed for the lab offerings given to the patients.
If both parties are on board with the system, they may split the proceeds from the second claim filed.
Instructions and Guidelines
- Use this modifier when laboratory processes are performed by someone or something other than the treating or reporting doctor.
- This modifier may only be used in conjunction with clinical laboratory tests.
- Impartial clinical laboratories may submit this modifier to imply that the service was referred to an outside laboratory.
- Payment for clinical lab tests relating to schedules is generally made only to the individuals who conducted or supervised the tests. Payment may be made to one impartial or hospital laboratory for examinations conducted by another lab under an exception to strategy (the referring lab).
Some offices that are part of a bigger hospital or institution may be unsure about the secure coding regulations, but it is essential to keep in mind that only one provider should be paid for the lab – not have both. If the lab is validly charging customers for the lab test, the provider will be able to bill only for the venipuncture (only one charge per encounter, regardless of the number of labs ordered).
You can always notify us if you need assistance with your billing. We have a knowledgeable coding team that uses correct modifiers to avoid refusals. To learn more about our medical billing services, please contact us at rcmexpertz@gmail.com
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