The Artery is your community for finding solutions to your day-to-day clinical chemistry questions. Last month, several answers were found to questions ranging from “Does your lab perform annual/periodic carryover assessment of analyzers with automatic pipetting systems?” to “Are the methods you use for AST & ALT supplemented with P-5’-P?”. Read on for our editor’s picks of the best discussions on the Artery in February.
Pathology Review for Absolute Lymphocyte Count
Initiated by @Richard Hancock, MT (ASCP)
One member is wondering if other labs could share their upper limits for absolute lymphocyte count on a peripheral smear that requires a pathologist review. Most respondents use 5,000 x 10^3/uL as the threshold for doing a manual smear review. One lab only has techs check if any blasts were missed, though, and only requires a pathologist review if blasts are seen. Another respondent says you could probably use a higher threshold since you can’t even formally diagnose chronic lymphocytic leukemia (CLL) until you have more than 5,000 CLL cells.
Initiated by @David Alter, MD DABCC
One member thinks that pre-analytic errors should not be considered lab errors, and should instead be designated as prelab errors. A couple respondents argued against this, however, because pre-analytic errors do include errors by lab staff, such as incorrect sample handling or adding a test to the wrong patient sample. Another respondent also suggested that it would have a greater impact on quality to identify trends involving non-lab vs. lab errors in both the pre- and post-analytical phases, as this enables labs to better pinpoint both causes of error and solutions.
CAP Question – Carryover Studies
Initiated by @Bryan Robeson
Does your lab perform annual/periodic carryover assessment of analyzers with automatic pipetting systems? The CAP All Common Checklist states that labs should evaluate for carryover as part of the initial evaluation of the instrument and after major maintenance/repair. Respondents are split, however—some basically follow the CAP guidelines, but others don’t. One person in the latter group explains that, after an instrument’s initial evaluation, carryover testing only really needs to be done when a new test is added to the analyzer menu or potentially after replacement of automatic pipettor seals or probes.
Pyridoxal-5’-Phosphate (P-5’-P) Supplementation of AST and ALT Methods
Initiated by @David Koch, PhD, DABCC, FAACC
Are the methods you use for AST & ALT supplemented with P-5’-P? So far, five respondents say yes. Particularly in Germany and the Netherlands, all labs use AST & ALT reagents with P-5’-P. Three respondents say no, one of whom is in Japan, where P-5’-P is not recommended. However, three people thought their methods were supplemented only to find out they aren’t—including the original poster, who only discovered this problem after clinicians at his institute were confused by some very low AST & ALT results.