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 “Which equation do labs use to calculate eGFR using serum creatinine values?” to “What is the difference between a lead test that is marketed as an Occupational Safety and Health Administration (OSHA) lead test versus a plain lead test?”. Read on for our editor’s picks of the best discussions on the Artery in November.
Quality Control StorageInitiated by
@Robert Rosecrans, PhD, ABB, FADLMOne poster is wondering why his lab was cited by a mock Joint Commission inspector for storing quality control material in the same refrigerator as patient specimens. In response, an Arterian who is a Joint Commission surveyor explained that reagents and specimens can be stored in the same refrigerator as long as precautions are taken to minimize the risk of contamination. Since the original poster’s current practices meet this standard, he realized the mock inspector simply misinterpreted the Joint Commission standards, which a couple other respondents warned often happens with mock inspections.
OSHA Lead vs. Lead ScreeningInitiated by
@Becky Brtva, ASCP, MT (ASCP)What is the difference between a lead test that is marketed as an Occupational Safety and Health Administration (OSHA) lead test versus a plain lead test? One Arterian responded that an OSHA webpage states that labs performing OSHA lead testing must meet the agency’s accuracy requirements in blood lead proficiency testing. According to the OSHA site, the agency also uses two different lead testing standards: a general industry lead standard and a construction lead standard.
Salivary CortisolsInitiated by
@Dianne Giddens, HHSIn a case where a patient’s serum cortisol levels have been consistently low, would salivary cortisol and ACTH testing also be helpful? According to one respondent, salivary cortisol reflects free bio available cortisol, which can be more relevant than the total cortisol levels reflected by serum cortisol. Another respondent added that early morning salivary cortisol testing could reduce the need for ACTH stimulation tests, but this approach requires further clinical validation. In the meantime, ACTH is indeed recommended for differentiating primary adrenal insufficiency from secondary.
eGFRInitiated by
@Saifuddin KhaledWhich equation do labs use to calculate eGFR using serum creatinine values? Out of the labs that have responded so far, 5 use CKD-EPI and 3 use both MDRD and CKD-EPI. 3 labs also elaborated that they use the Schwartz formula in pediatric patients, while for adults older than 70, 1 lab runs cystatin C and then applies the corresponding formula. Some researchers have also proposed a full-age spectrum formula to eliminate the discrepancies observed between the CKD-EPI and Schwartz formulas in patients who are 17 years old (the transition age between pediatric and adult care).