The updated FDA POCT glucose meter performance standard has a big problem

October 21, 2016


As readers may be aware, I have ranted against glucose meter standards for some time. Although the standards have many flaws, the most egregious one is the failure to specify 100% of the results. For POCT glucose meters, the CLSI standard C30-A2 (2003) adopted the ISO glucose meter standard 15197, which accounts for 95% of the results.

In 2013, CLSI updated its standard, now called POCT 12-A3 to include 98% of the results.

In 2014, FDA issued a draft POCT glucose meter guidance which covers 100% of the results.

But, now FDA has updated its POCT glucose meter guidance to cover only 98% of the results.

There’s no reason to allow 2% of the results to be unspecified – I don’t know why the FDA did this.

Interesting paper about Hb A1c

October 21, 2016


An upcoming paper about Hb A1c showed that MCH (mean corpuscular hemoglobin, a CBC parameter) correlated negatively with Hb A1c. In the patients studied, the effect at the extreme range of observed MCH could be as much as 0.7%-0.8% on HbA1c.


Glucose Error Grids – Well Known?

September 24, 2016


The picture shows a possible stranded sea creature at low tide, taken from 3,500 feet.

I was talking to a colleague about a project I’m working on and in order to explain, I asked him if he was familiar with glucose error grids. He said no, which surprised me. My colleague has been developing immunoassay reagents for a long time and while development and not evaluation is his specialty, as part of development, one must prove precision and accuracy.

I took this to mean that the concept of error grids is not that well known outside of diabetes. This is unfortunate, since error grids make more sense to me than total error, measurement uncertainty, or separate requirements for precision and accuracy.

I’m impressed

August 26, 2016


In my last blog entry, I noted that the problem with patent based QC is that publications talked about its benefits using simulations, but no one was actually using patient based QC. Well, the article that was upcoming has come out and these authors are using patient based QC and provide an example where a shift in sodium values was detected. So I’m impressed.

The problem with patient based QC

August 18, 2016


In an editorial (actually more of a mini review) in Clinical Chemistry, the various patient based QC methods are reviewed. The editorial is provided because of a companion article that has yet to appear.

One problem with patient based QC is that it is always compared to traditional QC, perhaps with the goal that it could replace traditional QC. But why not do both.

And perhaps a bigger problem is that people study patient based QC by performing simulations and/or providing examples showing that retrospective analysis of a (known) problem (perhaps a clinician complaint) would have been detected by patient based QC.

But I am not aware of anyone routinely using patient based QC (with or without traditional based QC), for all assays.

Theranos Board now populated with past AACC presidents

August 10, 2016


Theranos has been criticized for its board, which has two former secretaries of state (Henry Kissinger and George Schultz), two former senators and several former high ranking military officers and not much in the way of scientific expertise. Now, their scientific and medical advisory board includes four former AACC presidents: Susan Evans, Ann Gronowski, Larry Kricka, and Jack Ladenson. Note that although clinical chemists have been added, the fact that past presidents have been chosen conforms to Theranos’s strategy of favoring “official” types.

So here’s a question – if you were a well-known clinical chemist, would you accept a position to serve on Theranos’s board?

More AACC 2016 Philadelphia Notes

August 4, 2016


As for the AACC 2016 app, it deconstructs the three program books into something pretty useless. With the physical books, one can page through them rather quickly. But with the app, most of the titles are cut off, so it takes forever to find things.

The posters were so far away, they seemed to be in a different zip code.

Several posters were interesting and I was impressed by a poster presented by Linda AC De Grande about the use of patient medians. Maybe one day QC using patients will be mainstream.

Although I’m no longer part of CLSI, I have attended CLSI meetings at the AACC national meeting since the 80s. But these meetings are not held any more at the national AACC meeting. This makes CLSI less inclusive since people can no longer simply drop in on the meetings.

Anyone who stayed at the Marriott (like me) was very happy since the convention center was a block away.

At a Siemens presentation about IQCP, it was implied that conducting IQCP might allow one to run QC less than once a month as long as there was no conflict with manufacturer’s IFU. Not sure if the presenter was correct but a scary thought nevertheless.