The Essence: The Best of January 2020

By Anne-Margaret Olsson posted 20 days ago

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 “What reference range do labs use when running quantitative hCG on males?” to “What is your critical value notification process?” Read on for our editor’s picks of the best discussions on the Artery in January.

Quantitative hCG on Males
Initiated by @Linda England, MT (ASCP)

What reference range do labs use when running quantitative hCG on males? Respondents say that hCG in men should normally be undetectable, and that each individual lab should verify a male reference interval for its own local population. Because labs frequently don’t know whether an hCG test was ordered as a pregnancy test or as a tumor test, one respondent also adds that all serum hCG assays used in clinical labs should detect both hCG and the major hCG variant (and tumor marker) free beta subunit.

SPE Narrative
Initiated by @Trevor Campbell, MLT

Do other labs report findings on SPE apart from M-spikes? Several respondents do, arguing that it would be a shame to waste all of the information SPE gives and that this is one area where clinical pathologists/chemists can use their skills to aid in patient diagnosis. However, a couple respondent’s labs don’t. For one respondent, this is because his institution’s physicians really don’t use SPE for hepatic or renal problems. Overall, the SPE findings that a lab reports seem to depend on the lab’s relationship with their clinicians.

Venous Blood Gas Sample Collection
Initiated by @Shahannim Izham

For venous blood gas (VBG) testing, one institute collects venous blood either in a 10cc syringe or lithium heparin tube, then transfers some into a 1cc heparinized syringe to run the test. Is this okay? Respondents say the sample should be drawn directly into a heparinized syringe and kept anaerobic. Some do use lithium heparin tubes in certain cases, but this is not ideal. One respondent also recommends that the original poster run the VBG from the 10cc syringe before expelling for other testing in order to minimize air exposure to the sample for the VBG.

Obinutuzumab (Gazyva) on Immunotyping
Initiated by @Olajumoke Oladipo, MD, DABCC, FAACC

One AACC member is wondering if other labs have noticed an interfering peak from obinutuzumab on serum protein immunotyping. Her lab has never seen the same interference with rituximab, even though both drugs are anti-CD20s (IgG kappa). Some respondents think this difference could be caused by the fact that therapeutic concentrations of rituximab are lower than those of obinutuzumab. Another respondent, meanwhile, says she tends to see interference in SPEP with human antibodies (which obinutuzumab is), and points out that rituximab is a hybrid antibody.

Critical Value Notification Process
Initiated by @Wendy Shea, MT (ASCP)

For those in hospital labs, what is your critical value notification process? The original poster’s lab currently has a tech release the result call, but this takes up too much tech time due to issues such as the nursing station not answering the phone or doctors for outpatients not calling back. One respondent’s lab has solved this problem by using a call center, but other labs say they wouldn’t have the money for this. Another respondent’s lab calls the operator and asks them to page the provider on call for the patient’s service team.