This Week in Clinical Chemistry

Researchers led by George Ruijter from the Erasmus MC University Medical Center in The Netherlands describe their use of a rapid ultraperformance liquid chromatography-tandem mass spectrometry assay to detect the tetrasaccharide 6-α-D-glucopyranosyl-maltotriose, or Glc₄, in urine. As the researchers note in an online, early Clinical Chemistry article, Glc₄ is a possible biomarker for a number of glycogen storage diseases. In this paper, the researchers report that their assay is "rapid and analytically specific" and "precise within acceptable limits." Though it cannot distinguish among types of glycogen storage diseases, they say the assay "is potentially suitable for convenient therapeutic monitoring without a derivatization step that is required in other methods."

Also in Clinical Chemistry, a team of researchers in the UK examine under- and over-requesting of pathology tests, using the diabetes Hb A_1c test as a guide. The team looked at 519,664 Hb A_1c test requests from 115,730 patients made at the University Hospital of North Staffordshire, and reports that 49 percent of the requests did not follow established guidelines. "Although overrequesting was common, underrequesting was more prevalent, potentially affecting longer-term health outcomes," the team writes. "National guidance appears to be an ineffective approach to changing request behavior, supporting the need for a multisystem approach to reducing variability."