Abbott ARCHITECT Syphilis TP Chemiluminescent Immunoassay Accurately Diagnoses Past or Current Syphilis in Pregnancy.

OBJECTIVE: We evaluate diagnostic accuracy of the ARCHITECT chemiluminescent immunoassay (CIA) screening test in pregnancy, and evaluate pregnancy outcomes among screen-positive women. STUDY DESIGN: Samples from routine prenatal rapid plasma reagin (RPR) tests were collected between June 22 and August 18, 2017 and frozen. Samples were batch-tested with the Abbott ARCHITECT syphilis TP immunoassay (CIA, index test). We calculated sensitivity, specificity, predictive value, and false positivity. We compared pregnancy and neonatal outcomes among screen-positive women. RESULTS: Of 1,602 specimens, 35 (2.2%) were RPR + ; of those, 24 (69%) were CIA +/Treponema pallidum particle agglutination assay (TPPA)+ and 11 (31%) were CIA-/TPPA-. Of 1,567 RPR- specimens, 14 (0.9%) were CIA + ; of those, 13 (93%) were TPPA + , and one (7%) had a false positive CIA test. Sensitivity of the CIA (95% CI) was 100% (90.5-100%), specificity 99.9% (99.6-100%), positive predictive value 97.4% (86.2-99.9%), and false positive rate 0.06% (0.002-0.4%) for current or past syphilis. Among 37 CIA +/TPPA+ women, seven (19%) had RPR-negative status (Group 1), 11 (30%) had previously treated syphilis (Group 2), and 19 (51%) had active infection (Group 3). One stillbirth occurred in a woman with early, active syphilis identified at delivery; no adverse perinatal outcomes occurred among women in Groups 1 or 2. CONCLUSION: The ARCHITECT syphilis TP immunoassay accurately diagnoses current or past syphilis in pregnancy. Clinical history and staging remain essential using a reverse algorithm.

UV-triggered affinity capture identifies interactions between the Plasmodium falciparum multidrug resistance protein 1 (PfMDR1) and antimalarial agents in live parasitized cells.

A representative of a new class of potent antimalarials with an unknown mode of action was recently described. To identify the molecular target of this class of antimalarials, we employed a photo-reactive affinity capture method to find parasite proteins specifically interacting with the capture compound in living parasitized cells. The capture reagent retained the antimalarial properties of the parent molecule (ACT-213615) and accumulated within parasites. We identified several proteins interacting with the capture compound and established a functional interaction between ACT-213615 and PfMDR1. We surmise that PfMDR1 may play a role in the antimalarial activity of the piperazine-containing compound ACT-213615.

Increased rates of blood culture contamination during the coronavirus disease 2019 pandemic.

We observed a higher rate of blood-culture contamination during the COVID-19 pandemic at our institution compared to a prepandemic period. Given the potential implications of blood contamination in antibiotic and diagnostic test utilization as well as added cost, it is imperative to continue efforts to minimize these episodes during the pandemic.

Susceptibility of Cardiac Troponin Assays to Biotin Interference.

OBJECTIVES: To investigate biotin interference on three cardiac troponin (cTn) assays and demonstrate a method to overcome biotin interference. METHODS: cTn levels were measured in (1) plasma from healthy volunteers on 10-mg daily biotin supplementation mixed with a plasma with known elevated troponin, (2) plasmas with known elevated cTn after mixing in reagent biotin to simulate supplementation, and (3) biotin-spiked plasma specimens pretreated with streptavidin-agarose beads. RESULTS: Daily biotin ingestion (10 mg) and studies simulating daily biotin use resulted in significant interference in the Gen5 cardiac troponin T (cTnT) assay; the contemporary Gen 4 cTnT and high-sensitivity cardiac troponin I (hs-cTnI) assays were unaffected. The biotin interference threshold was 31, 315, and more than 2,000 ng/mL for Gen5 cTnT, cTnT, and hs-cTnI assays, respectively. Streptavidin pretreatment blocked biotin interference in cTn assays. CONCLUSIONS: Biotin interference is possible at plasma concentrations achievable by ingestion of over-the-counter supplements that may lead to delayed or missed diagnosis of myocardial injury with the Gen5 cTnT assay.