Recent Artery Conversations

Discordance between serum free light chain measurement and protein electrophoresis

We have a perplexing case involving a patient whose kappa light chain is consistently above the linear limit of the assay, which is approximately 6,500 mg/L. Offline dilutions suggest the actual result may be up to 10 times that amount. Yet, the patient's total protein and gamma globulins are below normal, and the monoclonal light chain is barely detectable and below quantifiable limits (approximately 0.1 g/dL) by capillary electrophoresis (Sebia). The lambda light chain assay results are in the normal range. We suspect there may be an interference with the kappa light chain assay, but I cannot find any reports of this in the literature. Has anyone else observed a similar discordance between FLC and SPEP results? We are trying to locate a laboratory that uses the Diazyme FLC assay to compare results.

Please share.

Discrepancy in lactate values

We have a patient with AML, and their WBC count is 100 K/ul. The lactate measurement obtained from the blood gas instrument is 7.5 mmol/l, while that from the core lab instrument is 1.3 mmol/l. We repeated the measurement using new specimens, and the results were consistent. The patient has no history of Ethylene glycol ingestion; however, high ketone bodies were found in their urine (diabetic ketoacidosis). How should I proceed to investigate this discrepancy? Do you have any other suggestions?

Please share.

Carbohydrate-rich diet prior to 3 hour glucose tolerance?

Interesting I could not find this in the search of past artery posts, but nevertheless, I am curious about various lab practices as it relates to the 3 hour (or other) glucose tolerance test. For years, many labs have had guidance that goes out to patients with something to the effect of, "Diet prior to testing day should include at least 150 gms of carbohydrates, but otherwise keep your diet the same." In my internet searches, there are many labs out there that still have this in their patient instructions. Many other labs do not say one way or another. I have also seen recommendations that say "no specific diet." I do not think there are official policy guidelines or recommendations from societies regarding this matter, but maybe I am missing it?

Please share.


Connect. Grow. Advance.

ADLM brings together the world of laboratory medicine to exchange best practices, learn about the latest biomedical science, and network with like-minded professionals from across the globe.