Recent Artery Conversations
Have you encountered any erroneous total PSA high flyers in your lab?
We test the total PSA on the Beckman Coulter DXI800 using the Access Hybritech PSA assay, and we've recently received multiple complaints about erroneous high total PSA results. Typically, the patient has a non-detectable total PSA (<0.01 ng/mL), followed by a borderline high result (1.3-2.7 ng/mL). When the patient was retested (usually within a week because both providers and patients are concerned about tumor recurrence), the result returned to undetectable levels. Unfortunately, by the time we received the complaint, the specimens had already been discarded. However, we've ruled out other possible reasons, such as mislabeling, QC issues, instrument problems, carryover, and imprecision.
I am preparing for an upcoming workshop next week for LabVine on Digital Transformation: "A problem that can be solved ONLY through digital transformation." (Improving the effectiveness of QC) While researching the history of QC, I am referencing Westagrd's original QC algorithm article from 1981 "A Multi-Rule Shewhart Chart for Quality Control in Clinical Chemistry" I became curious about the difference between a Shewhart Chart and Levey-Jennings chart. In the article, he treats them the same saying "Control data are displayed on control charts, which are sometimes referred to as "Shewhart charts" and other times as "Levey-Jennings charts." I once thought the difference was that Schewart charts plotted all points from one day on the same vertical line on the daily axis, whereas LJ charts plot one run at a time, even if there are many in one day.
What do you think? Which chart are we really using?
There are many possible causes of a psychotic episode in a patient, some of which are related to organic conditions that can be tested for (some infections, autoimmune conditions, Wilson's, B12/folate deficiency etc). The probability of a positive result for various tests will depend on the nature of the patient and the presentation. My question is whether any of my ADLM colleagues have protocols for laboratory investigation of a 1st psychosis that they are able to share.