Pathology/Lab Coding Alert

When a payer assumes that you've either unbundled or duplicate-billed, modifier -59 (Distinct procedural service) and -91 (Repeat clinical diagnostic laboratory test) can tell it otherwise. The problem is knowing when and how to use each modifier for multiple services, repeat tests or bundled procedures.

Instructions for modifiers -91 and -59 and circumstances for their use sometimes appear to overlap "" says Kenneth Wolfgang MT (ASCP) CPC CPC-H director of coding and analysis for National Health Systems Inc. a coding consultation company in Camp Hill Pa. Even knowing when to use a modifier and when to report unmodified multiple units of service is not always clear.

Not every repeat lab test requires modifier -91 and not every distinct service requires modifier -59. ""To sort out which modifier to use you have to know the reason that the two tests were ordered together and your payers' rules for the claim "" Wolfgang explains.

Even though CPT defines modifier -91 as ""Repeat clinical diagnostic laboratory test "" not every lab test repeated for the same patient on the same day warrants using it. ""Only use -91 when it is medically necessary to obtain subsequent reportable test values "" says Anne Pontius MBA CMPE MT (ASCP) president of Laboratory Compliance Consultants Inc. in Raleigh N.C.

For example a patient with high blood pressure who has been on a low-salt diet may receive a plasma renin activity (PRA) test (84244 Renin) in the morning in the supine position. Because physicians may use variations in PRA levels due to time of day and patient position to evaluate certain conditions such as hyperaldosteronism they may order a repeat renin in the afternoon with the patient standing upright for a period of time. Report the second 84244 with modifier -91 to indicate that the lab performed two separate renin assays for the same patient on the same day.

You should use modifier -91 even if you conduct a lab test as part of a panel and repeat the test separately at another time of day Wolfgang says. ""On rare occasions it may be necessary to assign a -91 modifier even though you're reporting two different codes. It is appropriate to report -91 because you're repeating the same lab test for subsequent results.""

If the lab performs an electrolyte panel to evaluate acidosis for instance and the physician later orders a follow-up bicarbonate test report both 80051 (Electrolyte panel) and 82374 (Carbon dioxide [bicarbonate]). Append modifier -91 to 82374 to specify that you repeated the bicarbonate. Medicare's Correct Coding Initiative (CCI) edits require you to use modifier -91 in this instance to indicate that you did not ""unbundle"" the bicarbonate from the lab panel. Unbundling is erroneously reporting a single procedure with its component parts and billing for additional services.

If CPT provides a different code to describe a series of repeat lab tests (e.g. evocative/suppression panels) don't report each test code individually and don't use modifier -91 Wolfgang says. For instance unlike the earlier PRA example there are times when you should not bill two PRA tests for the same patient on the same day using 84244 and modifier -91. If the physician orders two PRA tests as part of an evocative/suppression panel to evaluate renovascular hypertension CPT lists a separate code for the service: 80417 (Peripheral vein renin stimulation panel [e.g. captopril]. This panel must include the following: Renin [84244 x 2]).

Evocative/suppression tests ""involve the administration of evocative or suppressive agents and the baseline and subsequent measurement of their effects on chemical constituents "" according to CPT. You should bill the panel code for the series of lab tests and if provided a separate code for administering the evocative/suppressive agent (e.g. 90780 Intravenous infusion for therapy/diagnosis administered by physician or under direct supervision of physician; up to one hour). For the renin stimulation panel after taking a baseline serum PRA test the physician gives the patient an oral dose of a suppressive agent such as captopril monitors the patient's blood pressure and draws a sample for a follow-up PRA test. Although the lab runs two PRA tests do not report 84244 and 84244-91. Rather bill the service as 80417

If you repeat a lab test to confirm initial results or resolve equipment errors don't bill the test code twice with modifier -91. ""Anytime a normal one-time reportable result is all that the physician needs for patient treatment you should not bill a repeat test that is conducted for quality-control purposes "" Pontius says. Only bill both services when obtaining subsequent reportable test values is medically necessary.

Use modifier -59 when you need to indicate that you performed a particular procedure independently of other services reported that day. Medicare's CCI edits list many ""bundled"" services a broader procedure that includes lesser services which you should not report together unless they are distinct and separate. Independent services may represent different sessions or body sites or separate excisions lesions or procedures. When you carry out a bundled procedure along with one of the lesser services performed independently use modifier -59 to show that you are not unbundling.

For example use modifier -59 if the lab performs tests for vitamins B-12 and B-3 for the same patient on the same day. Because the vitamin B-3 test has no specific code you must report it using general code 84591 (Vitamin not otherwise specified). CCI edits bundle this code with that for B-12 (82607 Cyanocobalamin [Vitamin B-12]) so you must use modifier -59 to indicate that you performed two distinct procedures.

Payers disagree about whether you should use modifier -59 to indicate distinct services when you perform the same procedure for different specimens. For example a pathologist might examine three separately identified skin lesions taken from different anatomic sites. Each examination warrants code 88305 (Level IV Surgical pathology gross and microscopic examination skin other than cyst/tag/debridement/plastic repair). Some carriers expect labs to report 88305 x 3 for these services. Others instruct labs to report 88305 for the first lesion then 88305-59 for each subsequent lesion. Still others require labs to report the multiple services with modifier -76 (Repeat procedure by same physician). Consult your carrier for specific instructions.

""Although it can be confusing there are times when you should report a repeat lab procedure with modifier -59 rather than -91 "" Wolfgang says. If the lab repeats the same CPT code not to obtain subsequent test values but to evaluate a different site use modifier -59 instead of -91.

For instance if you perform cultures from lesions at two different anatomic sites you should report 87070 (Culture bacterial; any other source except urine blood or stool with isolation and presumptive identification of isolates) and 87070-59 for the second culture.