Don’t Look Past Modifiers 90-99

CPT^® modifiers 90, 91, 92, and 99 often are overlooked by providers and coders. Whether coding lab procedures or procedures requiring multiple modifiers, it’s important to understand the correct usage and guidelines for reporting these modifiers.

Modifier 90

The CPT^® 2010 states to use modifier 90 Reference (outside) laboratory for reporting lab services performed by an outside or reference lab. It’s designed for situations where the provider reports a lab procedure that was, in fact, performed by an outside laboratory. Consult third-party payers before reporting modifier 90; exact usage rules vary by payer.
For example, a patient presents to the office for an automated complete blood count. The blood is drawn by office staff, and the specimen is sent to an outside lab for processing. Appropriate coding in this case is 36415 Collection of venous blood by venipuncture, 85027-90 Blood count; complete (CBC), automated (Hgb, Hct, RBC, WBC and platelet count). Append modifier 90 to the CPT^® code describing the CBC to indicate that although the provider is reporting the procedure, it actually was performed by an outside lab.
In such cases, according to Deb Grider’s Coding with Modifiers, the lab generally will bill the physician’s office for its service, and the office will in turn bill the patient for the lab.

Modifier 91

Use modifier 91 Repeat clinical diagnostic laboratory test to report the same lab test when performed on the same patient, on the same day, to obtain subsequent test results.
Modifier 91 causes a lot of confusion when differentiating its use from that of modifier 59 Distinct procedural service. When reporting lab procedures, use modifier 59 when the same lab procedure is done, but different specimens are obtained, or the cultures are obtained from different sites.
The June 2002 CPT^® Assistant provides a great example of the correct use of modifier 91:
A 65-year-old male patient with diabetic ketoacidosis has multiple blood tests performed to check the potassium level following subsequent potassium replacement and low-dose insulin therapy. After the initial potassium value, three subsequent blood tests are ordered and performed on the same date following the administration of potassium to correct the patient’s hypokalemic state.
Coding for this scenario would be:
84132 Potassium; serum, plasma or whole blood
84132-91
84132-91
84132-91
Per CPT^® guidelines don’t use modifier 91 to report lab tests that are repeated to confirm the initial results, due to malfunctions of either the testing equipment or the specimen, or when another appropriate one-time code is all that is needed to report the service. If the test is rerun to confirm the initial results or because of a malfunction of the equipment, the service cannot be coded and modifier 91 would not apply.
If multiple tests are run, but a single code describes the test, only report one code, and modifier 91 would not apply. For example, 82951 Glucose; tolerance test (GTT), three specimens (includes glucose) includes three specimens so if three specimens were obtained during the encounter, only report 82951.

Modifier 92

Append modifier 92 Alternative laboratory platform testing when lab testing is done using a transportable kit with a single use, disposable analytical chamber. CPT^® states the test does not require permanent space, and it can be hand held and carried to the patient for immediate testing.
As explained in CPT^® Assistant (March 2008, page 3 and April 2008, page 5), the use of this modifier 92 is limited to three specific lab procedures dealing with HIV testing:
86701 Antibody; HIV-1
86702 Antibody; HIV-2
86703 Antibody; HIV-1 and HIV-2, single assay
For example, a female patient presents to the office for a sexually transmitted disease (STD) screening. The patient is concerned about HIV exposure after engaging in unprotected sexual intercourse. The patient is tested for HIV using a hand-carried transportable kit. Correct coding in this case would be 86701-92. Modifier 92 is appropriate because the HIV testing is performed using the hand held transportable kit.

Modifier 99

Modifier 99 Multiple modifiers often is not reported because many coders and providers are not aware of its correct use. Modifier 99 is designed for situations where two or more modifiers may apply to the procedure, and notifies the payer that multiple modifiers are being reported. According to Ingenix’s Medicare Desk Reference for Physicians, the Centers for Medicare & Medicaid Services (CMS) does recognize modifier 99, as do most third-party carriers; however, the modifier is “informational only” and its use does not affect claims’ payment.
Correct reporting of modifier 99 varies by carrier; but, the most common usage is to report the procedure and to append modifier 99 immediately after, then report any additional modifiers. Coders and providers should refer to their third-party payer guidance for correct reporting of modifier 99.
As an example, a physician assists with the percutaneous skeletal fixation surgery of a patient’s posterior pelvic bone fractures, resulting from a severe, head-on car accident in which the car rolled several times. In this case, correct coding would be 27216-99-80-50 Percutaneous skeletal fixation of posterior pelvic bone fracture and/or dislocation, for fracture patterns that disrupt the pelvic ring, unilateral (includes ipsilateral illium, sacroiliac joint and/or sacrum). It is appropriate to append Modifier 99 to the procedure code here because more than one modifier is being reported for the surgical procedure. Modifier 80 Assistant surgeon indicates the physician’s role as an assistant surgeon, while modifier 50 Bilateral procedure denotes that this was a bilateral procedure.
Dawson Ballard, Jr., CPC, CEMC, CCS-P, is the coding educator for Take Care Health Systems, a Walgreens Company, in Franklin, Tenn.