Oncology & Hematology Coding Alert

Remember: INR and E/Ms don’t mix.

International normalized ratio (INR) monitoring is necessary whenever a patient undergoes anticoagulant therapy using a drug such as warfarin (brand names Coumadin or Jantoven). If the drug dosage is too little, the patient stands the risk of blood clots forming in the veins of their body; if it is too great, the patient’s blood will become so thin that clots will not form at all.

That means your provider must monitor the level of the anticoagulant in a patient’s blood very closely. And it means you must not only know your way around the INR diagnostic testing CPT^® codes but also around the associated diagnosis, management visit, and patient training service codes as well.

Fortunately, we’ve broken them all down for you, so you can code INR monitoring by the numbers.

1) Know Your Clinical Terms

INR measures prothrombin time, or the amount of time the blood takes to clot. The ratio part refers to the relationship between the patient’s prothrombin time and an international reference standard for clotting time (hence the terms “international” and “normalized”). When measured over time for a patient undergoing anticoagulant therapy, an INR can determine how effective the prescribed anticoagulant drug dosage is for reducing the patient’s clotting time.

2) Know Your INR Monitor Training Code

Your provider can monitor INR results by ordering labs using a venous blood draw or having the patient come to the provider’s office for testing. The testing in the provider’s office may also be a venous blood draw; however, more often it is a fingerstick specimen collection generating a fast result so the clinical team and/or the treating practitioner can make the necessary adjustments to the patient’s medication regimen. Increasingly, however, providers are having patients monitor their own INR results using a test meter.

When that happens, you’ll be able to report 93792 (Patient/caregiver training for initiation of home international normalized ratio (INR) monitoring under the direction of a physician or other qualified health care professional, face-to-face, including use and care of the INR monitor, obtaining blood sample, instructions for reporting home INR test results, and documentation of patient’s/caregiver’s ability to perform testing and report results) for the training involved in having the patient use and care for an INR monitor and report the results back to the provider. This training must be provided face-to-face.

Heads up: If your office supplies the INR monitor and test strips, you can report them separately using 99070 (Supplies and materials (except spectacles), provided by the physician or other qualified health care professional over and above those usually included with the office visit or other services rendered (list drugs, trays, supplies, or materials provided) or G0249 (Provision of test materials and equipment for home INR monitoring of patient with ... venous thromboembolism who meets Medicare coverage criteria; includes: provision of materials for use in the home and reporting of test results to physician; testing not occurring more frequently than once a week; testing materials, billing units of service include 4 tests) for Medicare patients. If you use code 99070, be sure to provide a description of the supplies utilized. Additionally, consider sending a copy of the supplier invoice to support the pricing information.

3) Know Your INR Management Code

Once your provider begins patient management using INR test results, you’ll use 93793 (Anticoagulant management for a patient taking warfarin, must include review and interpretation of a new home, office, or lab international normalized ratio (INR) test result, patient instructions, dosage adjustment (as needed), and scheduling of additional test(s), when performed).

Important: Unlike the codes it replaced in 2018, you won’t see any service period time limitations on 93793. You’ll simply report the code a maximum of once per day when a patient submits one or more new INR test results and your provider reviews and interprets them.

Red flag: There are several evaluation and management (E/M), assessment and management, and care management services that you cannot report with 93793 “because the management services [for 93793] would be normally included in the overall E/M service,” according to the March 2018 issue of CPT^® Assistant. They include:

• 99202-99215 (Office or other outpatient visit for the evaluation and management of a new/established patient …)
• 99441-99443 (Telephone evaluation and management service by a physician or other qualified health care professional ... to an established patient, parent, or guardian ...)
• 99421-99423 (Online digital evaluation and management service, for an established patient ...)
• 99490/99491 (Chronic care management services ...)
• 99487/+99489 (Complex chronic care management services ...)

National Correct Coding Initiative (NCCI) “edits also exist for 98966-98968 (Telephone assessment and management service provided by a qualified nonphysician health care professional to an established patient, parent, or guardian ...), but you can override them with modifier 59 (Distinct procedural service) if you have supporting documentation,” says Leah Fuller, CPC, Consultant, Pinnacle Enterprise Risk Consulting Services LLC in Charlotte, North Carolina.

That means ensuring that there have been no 93793 services provided to the patient “within the previous 7 days leading to an assessment and management service, or that the telephone service has not led to a 93793 service within 24 hours after the call. In order to apply modifier 59, you would have to prove that the telephone assessment was for a different diagnosis not relating to the anticoagulation,” adds Lori Carlin, CPC, COC, CPCO, CCS, director of professional coding services at Pinnacle Integrated Coding Solutions.

Keep in mind: You can also report a significant, separately identifiable E/M with 93792 “when the effort expended for the E/M services is significant enough to be separately reported and is separate from the effort needed to evaluate the patient for home and outpatient INR monitoring” (per the same issue of CPT^® Assistant), providing you append modifier 25 (Significant, separately identifiable evaluation and management service by the same physician or other qualified health care professional on the same day of the procedure or other service) to the E/M. But be sure to check NCCI edits to determine which E/M services you can report with 93792, as some E/M services will include the work of 93792. For example, 93792 can never be reported with 99490.

4) Know Your INR Management Dx Codes

If warfarin therapy is the reason for the INR test monitoring, you should report Z79.01 (Long term (current) use of anticoagulants) as the primary diagnosis.

You should also report a secondary diagnosis for the underlying reason for the warfarin therapy, which could include codes from D68.5- (Primary thrombophilia) or I82- (Other venous embolism and thrombosis) among others.