The results of the new method correlated well with the existing reference assay Y (new method) = 0.974 x (reference method) + 4.9, r = 0.9990, n = 52. Bilirubin with a concentration up to 60 mg/dL and lipemic index up to 389 did not show significant interference. No significant carryover was detected. The average standard deviation index in proficiency testing was 0.03 ± 0.29. The reference range was less then 22 mg/dL. Conclusions Plasma cell-free Hb measurement using the HI check function meets the analytical requirements of the plasma cell-free Hb assays. It is simple and cost-effective.Background Plasma ammonia is commonly measured in the diagnostic evaluation of hospitalized newborns, but reference values are not well defined. Methods We prospectively enrolled newborns admitted to the level III/IV neonatal intensive care unit and level II intermediate special care nursery from January 2017 to January 2018. Infants with inborn errors of metabolism or liver disease were excluded. Plasma ammonia concentrations were measured once within the first week of life and evaluated by sex, gestational age, timing of the draw, blood collection method, and type of nutrition. Reference intervals were calculated. Results 127 neonates were included; one third (34%) were term infants born at ≥37 weeks gestation, and two thirds (66%) were born preterm at less then 37 weeks gestation. Median plasma ammonia concentrations were 32 μmol/L (range less then 10 to 86 μmol/L).  https://www.selleckchem.com/products/mz-1.html  Median ammonia concentrations were higher among preterm compared to term infants (35 vs. 28 μmol/L, p = 0.0119), and term female compared to term male infants (34 vs. 26 μmol/L, p = 0.0228). There was no difference in median ammonia concentrations between female and male preterm infants, based on gestational age within the preterm group, timing of the blood draw, presence of hyperbilirubinemia, blood collection method, or type of nutritional intake. Conclusions Plasma ammonia concentrations among newborns are higher than the expected adult concentrations and may vary by gestational age and sex. Blood collection method, type of nutrition, hyperbilirubinemia, and timing of the draw do not impact concentrations. We propose a reference limit of ≤82 μmol/L for newborns less than one week of age.Background Carbamazepine is an effective drug for treating seizures and trigeminal neuralgia. Therapeutic drug monitoring of free carbamazepine in serum can be useful in situations that drug--protein binding is altered to guide regimen adjustment and to aid in the diagnosis of clinical toxicity. Methods Separation of the nonprotein bound carbamazepine was achieved via ultrafiltration through a molecular weight cut-off filter. A method for free carbamazepine measurement was developed on the automated cobas chemistry analyzers (Roche Diagnostics) by modifying the Carbamazepine Gen 4 assay (Roche Diagnostics). Assay performance characteristics were established including precision, accuracy, reportable range, analytical specificity, and stability. Results The intra- and inter-assay imprecision was 0%-1.4% and 2.4%-5.1%, respectively. The lower limit of quantitation was 0.3 µg/mL, and the assay was linear up to 10.0 µg/mL. A spike recovery study, using reference standard material, showed recovery was 93.5%--101.3% across the analytical measurement range. Method comparison with a reference laboratory method demonstrated equivalent performance with a slope of 1.01, intercept of 0.09, and correlation coefficient of 0.9948. Conclusion This assay provides a simple and accurate method for monitoring free carbamazepine with a fast turnaround time.Background Laboratorians have the opportunity to help minimize the frequency of adverse drug reactions by implementing pharmacogenomic testing and alerting care providers to possible patient/drug incompatibilities before drug treatment is initiated. Methods combining PCR with MALDI-ToF MS have allowed for sensitive, economical, and multiplexed pharmacogenomic testing results to be delivered in a timely fashion. Method This study evaluated the analytical performance of the Agena Biosciences iPLEX® PGx 74 panel and a custom iPLEX panel on a MassARRAY MALDI-TOF MS instrument in a clinical laboratory setting. Collectively, these panels evaluate 112 SNVs across 34 genes implicated in drug response. Using commercially available samples (Coriell Biorepository) and in-house extracted DNA, we determined ideal reaction conditions and assessed accuracy, precision, and robustness. Results Following protocol optimization, the Agena PGx74 and custom panels demonstrated 100% concordance with the 1000 Genomes Project Database and clinically validated hydrolysis probe genotyping assays. 100% concordance was also observed in all assessments of assay precision when appropriate QC metrics were applied. Conclusions Significant development time was required to optimize sample preparation and instrumental analysis and 3 assays were removed due to inconsistent performance. Following modification of the manufacturer's protocol and instituting manual review of each assay plate, the Agena PGx74 and custom panel constitute a cost-effective, robust, and accurate method for clinical identification of 106 SNVs involved in drug response.Background Point-of-care testing (POCT) continues to expand worldwide. Concerns remain about result quality despite guidelines and standards that specify testing practices. To better understand POCT testing worldwide, we polled analysts to obtain their views on actual practices and needs for improvement. Methods An online questionnaire was constructed on SurveyMonkey, a commercially available website for conducting such surveys. POCT analysts were sought worldwide from a pool of healthcare providers subscribed to a westgard.com newsletter or visitors to westgard.com and/or LinkedIn to one of the authors. Results Seventy-three percent of testing occurred in hospitals with 64% conducted in specialty settings. Regulatory mandates were followed by 88%. For most, less than 100 tests were performed per day fewer less than 25 devices. Nurses top the list of analysts. All but 5% of analysts received some form of training primarily from manufacturers. Eighty-seven percent verified devices/methods prior to implementation.