Evaluation of Sensitive Analytes to Hemolysis Interference on an Automated Chemistry Analyzer.

BACKGROUND: Hemolysis is a common reason for specimen rejection in the laboratory. Our experience suggested that hemolysis (H) flag limits are too strict for some analytes leading to unnecessary specimen rejections. This study summarizes H flags for commonly rejected analytes on the Beckman Coulter DxC 700 AU analyzer. METHODS: We evaluated analytes with low-limit H flags and high rejection rates. These included: aspartate aminotransferase (AST), alanine aminotransferase (ALT), iron (IRN), potassium (K), direct bilirubin (DBIL), magnesium (Mg), amylase (AMY), sodium (Na), gamma-glutamyltransferase (GGT), phosphorus (PHOS), albumin (ALB), alkaline phosphatase (ALKP), and lactate dehydrogenase (LDH). Five patient plasma pools without hemolysis were made from 50 patient specimens. Neat pools were analyzed to establish baseline analyte concentrations. A hemolysate was created by diluting whole blood with distilled water. Each analyte was tested after spiking each pool with the hemolysate to specific hemoglobin concentrations corresponding to manufacturer's H flags. Percent differences were calculated between baseline pool means and each flag's pool mean. Acceptance limits were based upon the average of the 2019 CLIA and the method precision limits. Calculated percent differences greater than the acceptance limits were considered significant. RESULTS: Manufacturer-defined hemolysis flags can be updated to greater than 1+ for Na, K, and AST, greater than 3+ for ALKP, and greater than 4+ for AMY and Mg. No changes were noted for the remaining analytes. CONCLUSIONS: The hemolysis criteria set for ALKP, AMY, AST, Mg, K, and Na were updated in the Remisol Advance middleware, which led to a 56% reduction in rejected hemolyzed specimens.

A rare occurrence of Anaplasma-associated peritonitis.

Anaplasmosis or human granulocytic anaplasmosis is a tick-borne illness caused by the bacteria, Anaplasma phagocytophilum, resulting from an infected tick bite. Examination of a blood smear within the first week of exposure may show microcolonies of anaplasmae (morulae) in the cytoplasm of neutrophils that are highly suggestive of anaplasmosis but not definitive. We present the first case describing Anaplasma-related peritonitis and morulae in peritoneal fluid granulocytes in a peritoneal dialysis patient who developed anaplasmosis.

Comparison of antibody response durability of mRNA-1273, BNT162b2, and Ad26.COV2.S SARS-CoV-2 vaccines in healthcare workers.

OBJECTIVES: There are limited comparative immunologic durability data post COVID-19 vaccinations. METHODS: Approximately 8.4 months after primary COVID-19 vaccination, 647 healthcare workers completed surveys about COVID-19 vaccinations/infections and blood draws. The groups included participants vaccinated with mRNA-1273 (n = 387), BNT162b2 (n = 212), or Ad26.COV2.S (n = 10) vaccines; unvaccinated participants (n = 10); and participants who received a booster dose (n = 28). The primary outcome was immunoglobin anti-spike titer. Secondary/tertiary outcomes included neutralizing antibodies (enzyme-linked immunosorbent assay-based pseudoneutralization) and vaccine effectiveness (VE). Antibody levels were compared using analysis of variance and linear regression. RESULTS: Mean age was 49.7 and 75.3% of the participants were female. Baseline variables were balanced except for immunosuppression, previous COVID-19 infection, and post-primary vaccination time. Unadjusted median (interquartile range [IQR]) anti-spike titers (AU/ml) were 1539.5 (876.7-2626.7) for mRNA-1273, 751.2 (422.0-1381.5) for BNT162b2, 451.6 (103.0-2396.7) for Ad26.COV2.S, 113.4 (3.7-194.0) for unvaccinated participants, and 31898.8 (21347.1-45820.1) for participants administered with booster dose (mRNA-1273 vs BNT162b2, P <.001; mRNA-1273, BNT162b2, or boosted vs unvaccinated, P <.006; mRNA-1273, BNT162b2, Ad26.COV2.S, or unvaccinated vs boosted, P <.001). Unadjusted median (IQR) pseudoneutralization was as follows: 90.9% (80.1-95.0) for mRNA-1273, 77.2% (59.1-89.9) for BNT162b2, 57.9% (36.6-95.8) for Ad26.COV2.S, 40.1% (21.7-60.6) for unvaccinated, and 96.4% (96.1-96.6) for participants administered with booster dose (mRNA-1273 vs BNT162b2, P <.001; mRNA-1273, BNT162b2, or boosted vs unvaccinated, P <.028; mRNA-1273, BNT162b2, Ad26.COV2.S, or unvaccinated vs boosted, P <.001). VE was 87-89% for participants administered mRNA-1273 vaccine, BNT162b2 vaccine, and booster dose, and 33% for Ad26.COV2.S (none significantly different). CONCLUSION: Antibody responses 8.4 months after primary vaccination were significantly higher with mRNA-1273 than those observed with BNT162b2.