Overdiagnosis of Newborn Hyperbilirubinemia: A Natural Experiment in Quality Improvement Fundamentals.

Two hospitals noted increased newborn hyperbilirubinemia coinciding with an undisclosed total serum bilirubin (TSB) assay change. Clinicians rapidly applied quality improvement methodologies to ascertain increased jaundice evaluations, readmissions, and possible safety issues. Methods: In January 2020, 2 hospitals (A and B) transitioned to a new method of measuring TSB using a new clinical chemistry analyzer (Siemens Atellica CH), which measured TSB by vanadate oxidase assay instead of the previous diazo assay. Five affiliated hospitals (C-G) continued to utilize the diazo assay. This natural experiment led to a comparison of data across the 7 hospitals. We analyzed: (1) TSB levels, (2) hospital hyperbilirubinemia readmissions, and (3) paired TSB measurements comparing the diazo assay and vanadate oxidase method. Results: Compared to the 2019 baseline, Hospitals A and B had a significant increase in TSBs ≥17.0 mg/dl and TSBs ≥20 mg/dl in 2020; Hospitals C-G did not. Readmissions for phototherapy significantly increased in hospitals A and B in 2020 compared to 2019. Paired blood samples showed bias-elevated TSBs by vanadate assay compared to the diazo method. By 2021, the laboratory resumed processing TSB samples by diazo assay, and the frequency of elevated TSBs and hyperbilirubinemia readmissions returned to 2019 levels. Conclusions: Factitious TSB elevation related to an assay change significantly increased newborn hyperbilirubinemia evaluations and phototherapy readmissions. Imbedded quality improvement methodologies of careful structure, process, and outcomes review hastened resolution.

Effects of hemoglobin C and S traits on the results of 14 commercial glycated hemoglobin assays.

Glycated hemoglobin is widely used in the management of diabetes mellitus. At least 300,000 Americans with diabetes mellitus have the hemoglobin (Hb) C or S trait. The accuracy of HbA1c methods can be adversely affected by the presence of these traits. We evaluated the effects of HbC and HbS traits on the results of 14 commercial HbA1c methods that use boronate affinity, enzymatic, immunoassay, and ion exchange methods. Whole blood samples from people homozygous for HbA or heterozygous for HbC or HbS were analyzed for HbA1c. Results for each sample type were compared with those from the CLC 330 comparative method (Primus Diagnostics, Kansas City, MO). After correcting for calibration bias by comparing results from the homozygous HbA group, method bias attributable to the presence of HbC or HbS trait was evaluated with a clinically significant difference being more than 10% (ie, 0.6% at 6% HbA1c). One immunoassay method exhibited clinically significant differences owing to the presence of HbC and HbS traits.

A direct comparison between lamellar body counts and fluorescent polarization methods for predicting respiratory distress syndrome.

Our objective was to directly compare the diagnostic usefulness of lamellar body counting (LBC) and the TDx-FLM II assay (Abbott Laboratories, Abbott Park, IL) for predicting respiratory distress syndrome (RDS). This was a 5-year, retrospective, cohort study. A diagnosis of RDS was given to infants who received surfactant treatment and/or required ventilator support and/or continuous positive airway pressure for more than 24 hours. There were 172 infants without RDS and 12 with RDS included in the study. By using a TDx-FLM II cutoff of 55 mg/g or more for maturity, the sensitivity was 83%, specificity was 65%, predictive value of a mature result was 98%, and predictive value of an immature result was 14%. These results were similar to LBC using a cutoff of 50,000/microL or more with sensitivity of 92%, a specificity of 60%, a predictive value of a mature result of 99%, and a predictive value of an immature result of 14%. The LBC and TDx-FLM II methods have similar clinical usefulness.

Gene expression profiling of primary tumor cell populations using laser capture microdissection, RNA transcript amplification, and GeneChip microarrays.

Gene expression profiling from microdissected cell populations is a powerful approach to explore molecular processes involved in development and solid tumor biology. In this chapter, we detail robust and validated methods for tissue preparation and isolation of high-quality RNA from microdissected cell populations. A protocol is also provided for linear transcript amplification using as little as 10 ng of total RNA to produce labeled cRNA targets for hybridization to GeneChip high-density oligonucleotide microarrays. Particular emphasis is placed on troubleshooting each technical step in the protocol and measures of quality assurance for both RNA isolation and resulting microarray data.

Analytic performance of immunoassays for drugs of abuse below established cutoff values.

BACKGROUND: The analytic performance and accuracy of drug detection below Substance Abuse and Mental Health Services Administration (SAMHSA) cutoffs is not well known. In some patient populations, clinically significant concentrations of abused drugs in urine may not be detected when current SAMHSA cutoffs are used. Our objectives were to define the precision profiles of three immunoassay systems for drugs of abuse and to evaluate the accuracy of testing at concentrations at which the CV was <20%. METHODS: Drug-free urine was supplemented with analytes to assess the precision in three commercial drugs-of-abuse immunoassay systems below the SAMHSA-dictated cutoffs for amphetamines, opiates, benzoylecgonine, phencyclidine, and cannabinoids. Consecutive urine samples with signals associated with a CV <20% by Emit immunoassay and below SAMHSA cutoffs were then subjected to confirmatory analysis. RESULTS: The CV of all immunoassay systems tested remained <20% to drug concentrations well below SAMHSA cutoffs. The accuracy of urine drug-screening results between the SAMHSA-specified cutoffs and the precision-based cutoffs was less than accuracy for specimens above the SAMHSA cutoffs, but the use of the precision-based cutoff produced a 15.6% increase in the number of screen-positive specimens and a 7.8% increase in the detection of specimens that yielded positive results on confirmatory testing. CONCLUSION: The precision of three commercial immunoassay systems for drugs-of-abuse screening is adequate to detect drugs below SAMHSA cutoffs. Knowledge of the positive predictive values of screening immunoassays at lower cutoff concentrations could enable efficient use of confirmatory testing resources and improved detection of illicit drug use.