Billing Laboratory test with Inconclusive/Invalid test resul

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Posts: 59
Joined: Wed Mar 13, 2013 9:04 am

Fri May 11, 2018 5:28 pm

Good afternoon,

Can someone provide regulatory guidance on how to bill laboratory test with a result of inconclusive or the instrument's result was "Invalid Test Result" or "Unable to calculate due to interfering substances." Essentially the laboratory test was performed but the results were invalid either because it was inconclusive, the patient ate something that interfered with the result, or the machine malfunctioned before the results could be produced. Can the test be billed and if so, please provide the regulatory guidance.
Posts: 11
Joined: Fri Apr 13, 2018 11:54 am

Tue May 15, 2018 4:33 pm

Hi FJohnson,

I would question why you would not re-run the original test if you have inconclusive results. You could possibly be setting yourself up for legal medical care issues if the provider is making decisions based on faulty data. For example, if you suspect a fracture and the original radiographs are inconclusive, I would take the radiographs over again to confirm the fracture. Otherwise, this can lead to a malpractice issue.

I could not find any regulations that prohibits the clinic from billing these services with inclusive findings; however, I did find regulations on use of modifier -91, should you chose to retake the test.

From Noridian:

Modifier 91 - Repeat clinical diagnostic laboratory test


This modifier is used for laboratory test(s) performed more than once on the same day on the same patient. Tests are paid under the clinical laboratory fee schedule.

Correct Use
* For necessary tests to obtain subsequent (multiple) test results
* For tests performed on the same patient on the same day
* Used with laboratory tests paid under the clinical laboratory fee schedule
* Clinical Lab Improvement Amendment (CLIA) Waived Test
o If entity holds valid waiver certificate, append modifier QW

Incorrect Use
* May not be used when there are standard HCPCS codes available that describe the series of results (e.g., glucose tolerance tests, evocative/suppression testing, etc.)
* May not be used when tests are rerun to confirm initial results; due to testing problems with specimens and equipment; or for any other reason when a normal, one-time, reportable result is all that is required
* Does not replace modifiers such as RT, LT, 50, E1-E4, FA, F1-F9, TA, and T1-T9
Corporate Compliance Analyst
Seattle Children's Hospital
Seattle, WA
Posts: 1
Joined: Sat Jun 16, 2018 2:55 pm

Sat Jun 16, 2018 3:11 pm

The regulatory guidance that you will need to reference will be specific to the accrediting agency of your laboratory, which is could be CLIA (for labs of waived certification only) or if moderate or high complexity you are also either working with COLA or CAP. I would also highly recommend you review any state law that may be applicable as well. This is kind of tough question to answer without knowing what type of testing you are actually performing. In some genetic testing "inconclusive" may be a valid result for that patient so you would bill, I am thinking specifically pharmacogenetic testing. If it is a scenario where the patient ate something, or say the quantity was not sufficient for testing you would not bill for that service. Invalid results, as the previous poster mentions would most likely lead the laboratory to perform an additional test on the same specimen using the modifier mentioned. Laboratories should not be releasing results that are labeled either invalid or inconclusive unless the SOP's for that testing indicates those terms are acceptable and those SOP's have been signed off on by the accrediting agency upon inspection. Inconclusive is a valid result that the physician should then document the results of that test and make decisions on next steps for that patient.

Another example that comes up frequently in toxicology is when patient's scrape their pills into the urine specimen to cover up diversion. When a patient does this, what they don't realize is that only the parent drug will be recognized by the instrument and in many cases these samples cause the laboratory to pull all of the specimens that were on the instrument with that specimen, clean and reset all of the calibrations, controls and QA curves. In this scenario, most laboratories inform the provider of the "offending" specimen and request a new specimen be sent. Sadly, no testing that was performed on that specimen would be billable as the testing could not be completed.

Hope that helps,

Owner- Ilex Consulting, LLC-
Partner- Triple Threat Holdings, LLC
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