Transferring older posts – complete

July 7, 2017

All posts has been transferred. I deleted one post, which talked about my revised web site (which no longer exists). I also changed all links which referred to my now defunct web site. So with this post, there are 398 posts.

 


Overinterpretation of results – bad science

June 16, 2017

A recent article (subscription required) in Clinical Chemistry suggests that in many accuracy studies the results are overinterpreted. The authors go on to say that there is evidence of “spin” in the conclusions. All of this is a euphemistic way of saying the conclusions are not supported by the study that was conducted, which means the science is faulty.

As an aside, early in the article, the authors imply that overinterpretation can lead to false positives, which can cause potential overdiagnosis. I have commented that the word overdiagnosis makes no sense.

But otherwise, I can relate to what the authors are saying – I have many posts of a similar nature. For example…

I have commented that Westgard’s total error analysis while useful does not live up to his claims of being able to determine the quality of a measurement procedure.

I commented that a troponin assay was declared “a sensitive and precise assay for the measurement of cTnI” in spite of the fact that in the results section the assay failed the ESC- ACC (European Society of Cardiology – American College of Cardiology) guidelines for imprecision.

I published observations that most clinical trials conducted to gain regulatory approval for an assay are biased.

I suggested that a recommendation section should be part of Clinical Chemistry articles. There is something about the action verbs in a recommendation that make people think twice.

It would have been interesting if the authors determined how many of the studies were funded by industry, but on the other hand, you don’t have to be part of industry to state conclusions that are not supported by the results.

 


Blog Review

May 26, 2017

I started this blog 13 years ago in March 2004 – the first two articles are about six sigma, here and here. The blog entry being posted now is my 344th blog entry.

Although the blog has an eclectic range of topics, one unifying theme for many entries is specifications, how to set them and how to evaluate them.

A few years ago, I was working on a hematology analyzer, which has a multitude of reported parameters. The company was evaluating parameters with the usual means of precision studies and accuracy using regression. I asked them:

  1. a) what are the limits that, when differences from reference are contained within these limits, will ensure that no wrong medical decisions would be made based on the reported result (resulting in patient harm) and
  2. b) what are the (wider) limits that, when differences from reference are contained within these limits, will ensure that no wrong medical decisions would be made based on the reported result (resulting in severe patient harm)

This was a way of asking for an error grid for each parameter. I believe, then and now, that constructing an error grid is the best way to set specifications for any assay.

As an example about the importance of specifications there was a case for which I was an expert witness whereby the lab had produced an incorrect result that led to patent harm. The lab’s defense was that they had followed all procedures. Thus, as long as they as followed procedures, they were not to blame. But procedures, which contain specifications, are not always adequate. As an example, remember the CMS program “equivalent quality control”?


Transferring older posts

May 15, 2017

I have started the process of transferring older posts, which were in my now defunct website, to this blog. It will take a little while and additionally it will take some time for the search engines to catch up.


I’ve retired – sort of

May 11, 2017

As of the end of 2016, I stopped consulting. I still follow lab medicine topics that interest me, and will still publish both papers in journals and entries on my blog.

I ended my website KrouwerConsulting.com – it doesn’t work anymore – and I realize that some of my earlier blog entries can’t be accessed because they were on KrouwerConsulting.com (written before I started my current blog). I will fix this and transfer all of these entries to my current blog, as soon as I figure it out!

I want to thank all of my clients. Their problems kept me thinking and I enjoyed both the technical tasks and meeting people to discuss a variety of issues.

 


United Airlines and mission statements

April 29, 2017

Most people have seen the video of a passenger being forcibly pulled off a United flight. After some missteps, one would think that the CEO would say the right thing. But he said the following (as seen on CBS news on 4/27).

“Our policies were placed ahead of our shared values and procedures got in the way of what we know is right.”

To people like me, who have worked in industry, “shared values” sounds like a mission or vision statement. The problem is that a mission statement is supposed to dictate policies and procedures and of course, it is management that defines policies and procedures. Hence, the quote sounds hollow.

What a company does can be considered its mission. If it conflicts with its mission statement, then the mission statement is out of whack.


Overdiagnosis – the word makes no sense

April 13, 2017

In the recent hubbub about the use of PSA to screen for prostate cancer, the word overdiagnosis has appeared several times. In an online dictionary, it is defined as “the diagnosis of a disease more often than it is actually present.”

But the diagnosis of prostate cancer is pretty straightforward, with a biopsy determining whether cancerous cells are present. The diagnosis can be either correct or incorrect. But, there can be overtreatment, when low-risk prostate cancer is treated aggressively. So somehow, overtreatment has spilled over into diagnosis to produce the word overdiagnosis. That is, if a person has a biopsy confirmed prostate cancer, which is low risk and receives aggressive treatment – he has been over treated, not over diagnosed.