Ask the Expert with Barry Craig | June 2013

Are Waived instrument tests as accurate as full size analyzers? My office is reluctant to get Waived instruments because our doctors are not sure how usable the results would be.

 Waived instruments have gone through the FDA clearance process which includes method comparisons to other analyzers. These Waived instruments produce accurate results as long as two things happen.

  1. Proper training and competency of the user is established
  2. The manufacturer's guidelines for maintenance and quality control are followed.

These instruments are only as good as the person running them. Without proper training, the results may not meet the intended outcome

Our clinic found a cheaper urine dipstick to use on our analyzer. Is it OK to use a different brand?

You really need to check with the manufacturer. If the manufacturer's guidelines prohibit use of other dipsticks, you cannot. Even if this is allowed, and even if the "B" brand manufacturer claims compatibility, it is the lab's job to establish that the dipsticks perform as they should. Run controls, run patients using both dipsticks and compare results.

What do the regulations say about verification of performance specifications? I always understood it to mean that if we get a new instrument, we have to run on the new machine accuracy, precision, linear range and establish a normal range. One of the sales people is saying that they have published data that takes care of all that and that the manufacturer's rep will run anything that is additionally required.

If you purchase a new, FDA-cleared, Moderate Complexity analyzer, THE LAB must perform accuracy, precision, linear range and normal range. You can't use published data and you can't let a rep do it. The end user must perform the validations. This is one of the most cited regulations under CLIA.

Also, if you modify the test system, or use non-FDA cleared reagents, the test system then becomes High Complexity and all applicable regulations relating to High Complexity must be met. This includes higher personnel standards, additional validations, and additional regulations.

Now I have a challenge for you. (No Google search for the answer, that's cheating.)
What method, now obsolete, for determining blood sugar used cuprous ions that yielded a deep blue color with phosphomolybdic acid?

(Hint: It is not Somogyi-Nelson, but it has a two part name)

First to email the correct answer to gets a prize. Amazing riches await you if you can solve the puzzle.

Barry Craig


Expert on physician office laboratories and diagnostic equipment

Barry works almost exclusively with POLs and understands the needs and challenges they face. With more than 20 years of lab consulting experience, his company works with office lab start-ups, inspection follow-ups, and help with the CLIA, COLA and JCAHO regulatory issues offices face daily. He offers a unique insight and customer focused approach to the lab and its solutions. In his current role as President of Laboratory Consulting, LLC, Barry is leading the way for physician's offices to develop their in-house labs as a place to obtain fast, accurate results and maintain a healthy profit using the latest technology available.

Being in touch with the POL community nationwide his company has a unique insight into the problems and questions that arise from the operation of a POL.