Pathology/Lab Coding Alert

Question: When coding for a lab test, does it matter if the physician ordered the test for screening or diagnostic purposes? The lab performs the same test, so why would the coding be different?


Iowa Subscriber

Answer: Whether the physician orders a lab test for screening or diagnostic purposes can make a huge difference to your coding. Screening versus diagnostic testing can impact three aspects of coding:

1. Diagnosis code selection

The physician orders a diagnostic test because the patient has signs, symptoms or a condition or disease that requires further testing to delineate a diagnosis or treatment. You should report the ICD-9 code for the patient's condition as the reason for the test. For instance, when a physician orders a glucose test (82947, Glucose; quantitative, blood [except reagent strip]) for a patient with diabetes, you should report the appropriate diabetes ICD-9 code (from category 250.x, Diabetes mellitus) as the reason for the test.

On the other hand, a physician orders a screening test when the patient has no signs or symptoms of disease. You should report the ICD-9 code for a specific type of screening, which you'll find in the V73-V82 category codes.

2. Procedure code selection

Sometimes you'll have to use a different procedure code based on whether the test is for diagnostic or screening purposes, even if the lab test is no different.

A common example of this situation is coding for prostate specific antigen tests for Medicare beneficiaries. Medicare requires you to use the appropriate CPT code for a diagnostic PSA test (84153, Prostate specific antigen [PSA]; total) and the appropriate HCPCS Level II code for screening PSA tests (G0103, Prostate cancer screening; prostate specific antigen [PSA] test, total).

3. Coverage issues

Different coverage rules often apply for screening and diagnostic tests, and you have to consult the different rules to ensure that you can show medical necessity for the test. For example, Medicare delineates which ICD-9 codes it will cover for a diagnostic PSA test in a lab National Coverage Determination (NCD). Covered diagnoses include symptoms such as 788.41 (Urinary frequency) and diagnosed conditions such as 185 (Malignant neoplasm of prostate). One of these codes would show medical necessity for 84153.

But the NCD does not address coverage for a screening PSA test. Medicare's rules specify that you should report a screening PSA with ICD-9 code V76.44 (Special screening for malignant neoplasms, prostate). This code shows medical necessity for a screening PSA test (G0103), not the diagnostic test (84153).