In the previous issue, we discussed quality standards required to perform lab tests in clinical practice (see “What You Should Know About Lab Testing,” pg. 12, March/April issue). Now let us review key steps that will facilitate efficient coding and proper reimbursement for these diagnostic tests.

There are a variety of laboratory tests that nurse practitioners (NPs) and physician assistants (PAs) utilize on a regular basis when diagnosing and managing patients with autoimmune disorders. Commonly used tests include C-reactive protein, sedimentation rate, rheumatoid factor, complete blood count (CBC), urinalysis, comprehensive metabolic panel, antinuclear antibody (ANA) and uric acid. One may order these individually or in combination, depending upon one’s preference or the preference of the practice.

While these tests do fall under the same American Medical Association (AMA) guidelines of proper coding for the treatment of patients, there are certain nuances to coding these tests. Indeed, clinicians must have a good working knowledge of these codes in order to ensure appropriate reimbursement for these diagnostic tests.

What You Should Know About Recent Changes With Lab Panels
Lab panels have undergone significant changes in the past few years and continue to be a source of confusion. There is no longer a list of automated multi-channel tests. One should report tests individually unless they comprise one of the nine organ- or disease-oriented panels.

Clinicians should not order one of the organ- or disease-oriented panels simply as a convenience. If medical necessity is not present for even one of the tests on a panel, then the panel should be “broken” and one should report the medically necessary tests individually. The Centers for Medicare and Medicaid Services (CMS) maintain the list of appropriate diagnostic codes for each test. If you order a test that is not on the list of approved tests for the diagnosis code(s) you have listed for the patient, it is unlikely you will receive payment for the test. Providers should contact their Medicare carrier for the approved list of ICD-9-CM codes for each test routinely ordered.

In many cases, carriers have removed the non-specific or unspecified diagnosis codes from the approved lists. Health professionals should keep in mind that it is fraudulent to list a diagnosis that is not present so a test will be covered. However, it is not fraudulent to make a specific diagnosis based on your non-lab findings and then change the diagnosis if the lab work does not support your earlier conclusion.

OTHER KEY TIPS ON CODING FOR DIAGNOSTIC LABS

Ordering Diagnostic Tests: How To Ensure Proper Coding
To order lab tests for patients with arthritis or patients whom you suspect of having arthritis, clinicians should order each of the following tests individually. These tests are: uric acid, blood and chemical (CPT 84550); sedimentation rate, erythrocyte and non-automated (CPT 85651); fluorescent antibody, screen and each antibody (CPT 86255); and qualitative testing for rheumatoid factor (CPT 86430).

Always refer to the AMA CPT manual for a complete list of the appropriate codes for these tests. These tests include but are not limited to: erythrocyte sedimentation rate (ESR), synovial fluid analysis, complete blood count (CBC), fecal occult blood test, urinalysis, quantitative rheumatoid factor screen spun microhematocrit, antinuclear antibodies (ANA), complement functional activity, anti-DNA and anti-DNA titer.

It is not commonly known that there are separate codes to describe rheumatoid titer (CPT 86431, quantitative) and rheumatoid factor (CPT 86430, screen). One may code tissue typing as a single antigen (i.e, using CPT 86812 for HLA-B27) or multiple antigens (CPT 86813). Clinicians would use a separate code for HLA-DR/DQ typing with codes for single antigen (CPT 86816) and multiple antigens (CPT 86817).

Separate codes for complement C3 and complement C4 have been deleted from the CPT manual. If you are reporting C3 and C4 during the same visit, use CPT 86160 and indicate two units under 24G (days or units) on the CMS 1500 form. There is a separate code (CPT 86162) for CH50. If coding for an individual complement (i.e., C2), use CPT 86160 as well.

Obtaining Synovial Fluid: Key Points On Appropriate Coding
1. Gross examination (CPT 85810)
• Viscosity
• Color
• Clarity
2. Cell count miscellaneous body fluids
except blood
• Total white cell (CPT 89050)
• Total white cell count plus differential (89051)
• Crystal identification by light microscopy with or without polarizing lens analysis only body fluid; (except urine) (89060)
3. Glucose quantitative blood (except reagent strip) (CPT 82947) (Be sure to list the body fluid being analyzed in the narrative field.)

Ensuring Accurate Coding Of Follow-Up Tests
Keep in mind that Medicare carefully monitors follow-up testing. Listing disease-specific diagnosis codes will not be sufficient to prove medical necessity for drug monitoring. Health professionals must also list the ICD-9-CM codes that support medical necessity for high-risk medications. These codes include:
• V58.65: Long-term (current) use
of steroids
• V58.69: Long-term (current) use of other (high-risk) medications
• V67.51: Following completed treatment with high-risk medications that are not classified elsewhere

If your office processes laboratory tests, follow the key guidelines below.
• If you do testing in your own laboratory, bill for the test using the appropriate laboratory code number in addition to the office visit.
• If you collect a specimen and send it to an outside laboratory, bill for the office visit and a handling fee (CPT codes 99000-99002), or add the modifier “90” (or the five-digit modifier 09990) with the code for the test performed. This alerts third-party payers that an outside laboratory performed the tests and supports the billing by both the rheumatology practice and the laboratory.
Note: Medicare does pay for 36415 (venipuncture) to draw the blood specimen but does not pay for CPT codes 99000-99002. However, private payer payments vary.
• If the laboratory bills you for the test, bill the patient using the appropriate code from the laboratory section of the CPT manual. This only applies to non-Medicare patients who have laboratory tests performed by an outside laboratory. This must be billed directly by the outside lab. It should be noted that, at least in a few states, Medicaid and other third-party payers stipulate the same requirements.
• If you cannot locate a specific code for a test in the AMA CPT manual, try to locate the code based on the method of performing the test. Refer to the subsection information under the guidelines for the pathology and laboratory section.
• The allowable laboratory tests reimbursed for particular diagnoses are carefully monitored. Consult your Medicare carrier’s bulletin to identify the laboratory tests that will be reimbursed only if they correspond with the medically necessary diagnosis list.

In Conclusion
While coding for lab tests falls under the same AMA guidelines as proper coding for the treatment of patients, it is important to be aware of the nuances of these codes. Many carriers have removed non-specific or unspecified diagnosis codes from approved lists. In addition, lab panels have changed over the years and Medicare carefully monitors coding for follow-up testing.

In order to ensure proper office compliance and appropriate reimbursement, always refer to the AMA CPT manual for a complete list of the appropriate codes.

Editor’s note: For related articles, see “What You Should Know About Lab Testing” in the March/April issue of Arthritis Practitioner or “Essential Keys To Coding in 2007” in the January/February issue. For other articles, visit the archives at www.arthritispractitioner.com.