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The Essence: The Best of December 2019

By Anne-Margaret Olsson posted 01-06-2020 14:32

The Artery is a great resource for all AACC members—a place where you can ask your questions about laboratory practice and receive prompt, detailed responses. Each month our editor selects some of the best new Artery discussions. Below are our editor's picks for December.

How many decimals does your ultrasensitive-PSA have?
Initiated by @Charles Beavers, MD

The original poster’s lab recently changed to 2 decimal places, but he noticed that major reference labs vary a lot in how many decimal places they report (from 1 to 3) and is wondering what other labs do. A couple respondents say that labs should not report out to 3 decimal places unless they’ve validated PSA results to that decimal place. Another respondent provided a link to a paper on this issue that concludes that each lab must perform independent statistical analysis to determine the appropriate significant figure limitations for clinically relevant analytes such as PSA.

Critical Value; A New Definition
Initiated by @David Alter, MD DABCC

One AACC member has proposed defining a critical analyte as one where the patient is asymptomatic until they aren’t, i.e. by the time they become symptomatic, they are on the brink of becoming acutely symptomatic. Other members define a critical value as an imminently life-threatening test result, but agree that it’s difficult to decide what falls under this definition—especially since different clinicians want to be alerted about different results. Complicating matters further, there is also very little data to show that making critical calls changes patient outcomes.

Critical Threshold for Hypoglycemia
Initiated by @Robert Rosecrans, PhD, ABB, FAACC

Have any hospitals set their critically low glucose threshold to 54 mg/dL, the new value recommended by the American Diabetes Association? Many respondents have not, because they think the new threshold would increase the number of critical calls and tax their resources without impacting patient management. A couple labs have made the update, though. While one of these labs experienced an increase in critical calls, they also found that the new threshold enabled nurses (who perform many of their glucose tests with point-of-care meters) to institute better protocols for hypoglycemia.