I've enjoyed an interesting exchange with an engineer who contacted the American Society for Clinical Laboratory Science Consumer Forum. She was concerned that her blood specimen, which had been sent to two laboratories for complete blood counts, had generated the same hemoglobin result from each, however one reported the value as normal and the other as elevated. Applying an engineer's precision, she assumed one laboratory had made an error. Here is my response.

Back on February 14, Ann Tidwell posted a question on delta checks. Steve Duff at Precision BioLogic alerted us to a simultaneous critical values initiative.The North American Specialized Coagulation Laboratory Association (NASCOLA) has sent the following message...

From Richard Davis of Thermo Fisher, Inc.

Are you aware of any liquid stable coagulation controls? I understand Precision BioLogic has frozen controls, but one of our sales reps has been asked about liquid 2-8C stable materials.

I'm posting this message from Patty Erickson at Vanderbilt for assistance from any of our RAQA gurus participating in the blog:

Okay, I'm just not a chemist. I admit it. On my last CAP inspection I was cited for not performing AMR validations on my ELISA assays for anti-cardiolipin and beta-2 glycoprotein antibodies because I report these numerically for patient samples, as opposed to neg/pos. Here's the question. I have struggled with finding appropriate material to challenge the analytic range for each isotype and after speaking with a clinical chemist, it was suggested that I could use calibrators from a previous lot number kit (there are three different calibrators for each kit type) to challenge the AMR for a new lot number. That is what I am doing. But, since these kits are intended as semi-quantitative assays, the calibrators with assigned values from one lot number kit might not be expected to perform identically with a different lot number of the same type kit. What is my "target" for each calibrator, and what is my acceptance criteria ?  Lastly, in general, what is the "industry standard" for deeming an analytic range "validated" and if I fail this criteria, exactly what does one do for reporting off that particular lot number?  Have I confused anyone yet, besides myself? I am trying to satisfy those inspectors, but I am also trying to observe good laboratory practice. If anyone has specific information on how they go about doing this validation for ELISA assays, I would be so very, very appreciative!

From Kim Kinney at Clarian in Indianapolis:

Hi George,  I was wondering if I could get opinions on how techs feel about lyophilized vs. frozen calibrators, QC, and deficient plasmas?  I am partial to frozen because I think they behave more like plasma.  Lyophilized requires a reconstitution time and always seems to have a touch of "cloudiness" for lack of a better word! Any expert opinions out there?
 
Thanks, Kim

Hi, George,

We survived the validation and are very pleased with our new Beckman-Coulter TOP, but I have an issue with the new PTT therapeutic range we established for unfractionated heparin (UFH).

We collected many specimens over time, made sure they were double-spun and froze them at –70°C. Once we had the PTT validated and a reference range established, we started running chromogenic anti-Xa heparin assays and PTTs. We are still performing our anti-Xa assays on the MDA using the Stago Stachrom kit as we are waiting on the all-liquid heparin kit from IL. We had over 100 specimens but our range looked pretty flat! So we re-evaluated the results, and pulled out the ones that did not make sense (high PTT with little or no heparin) and threw in several fresh specimens. We came up with a range that (1) is much shorter and narrower than our previous range but (2) matched other TOP/Synthasil users so we felt comfortable.

We have had nothing but grief! We seem to be seeing many super-high PTTs right after bolus that we were not seeing before and it is difficult for the surgeons to hit that more narrow target. To make things worse, we are now being told our pharmacy is switching from Baxter heparin, due to the recall, to another brand and we will have to repeat! The pharmacy wants a range before they switch, which I have explained we cannot do since we do not have any patients to collect on the new heparin.

What would you recommend to the pharmacy? Should they stick with our current range and monitor with anti-Xa assays when needed until we can check the new range?

Sorry this is so long...cheers!
Kim Kinney, Clarian, Indianapolis

Kim Kinney at Indiana University Medical Center (and Clarian) wrote: