Establishment and application of a reverse dot blot assay for 13 mutations of hearing-loss genes in primary hospitals in China.

Background: Hearing loss is a common sensorineural dysfunction with a high incidence in China. Although genetic factors are important causes of hearing loss, hearing-related gene detection has not been widely adopted in China. Objective: Establishing a rapid and efficient method to simultaneously detect hotspot hearing loss gene mutations. Methods: A reverse dot blot assay combined with a flow-through hybridization technique was developed for the simultaneous detection of 13 hotspot mutations of 4 hearing loss-related genes including GJB2, GJB3, SLC26A4, and the mitochondrial gene MT-RNR1. This method involved PCR amplification systems and a hybridization platform. Results: The technique can detect 13 hotspot mutations of 4 hearing loss-related genes. And a total of 213 blood samples were used to evaluate the availability of this method. Discussion: Our reverse dot blot assay was a simple, rapid, accurate, and cost-effective method to identify hotspot mutations of 4 hearing loss-related genes in a Chinese population.

Syphilis as the great mimicker: A case of full-house pattern membranous nephropathy.

Syphilis is a known cause of membranous nephropathy. We describe a case of a patient presenting with nephrotic syndrome whose renal biopsy demonstrated a 'full house' immunohistochemical pattern with positive IgG, IgM, C1q, IgA, C3c, and C4d staining. He was treated with immunosuppressive agents for minimal change nephropathy and subsequently class V lupus nephritis, before syphilis infection was confirmed. Following treatment with a single dose of intramuscular benzathine penicillin there was complete and rapid resolution of nephrotic syndrome. With progressive rising incidence in the western world, syphilis is an important and under-recognised differential diagnosis in cases of nephrotic syndrome.

Application of Abbott ID NOW in the emergency department for SARS-CoV-2 detection: A medical center's perspective.

Testing for SARS-CoV-2 is crucial to tracking and controlling the pandemic. In particular, rapid testing in settings such as the emergency department (ED) could improve time to diagnosis and promote proper infection control measures. Early in the COVID-19 pandemic, we implemented the Abbott ID NOW COVID-19 method for screening symptomatic ED patients. However, due to concerns of suboptimal sensitivity, samples with a negative result were reflexed to the lab for confirmatory testing by the TaqPath COVID-19 Combo RT-PCR method. This study analyzed 6773 ID NOW results from April 2020 to September 2020 in the ED, of which 10% (n = 673) were positive and reported directly. The rest 90% (n = 6100) were negative and reflexed to RT-PCR. Among them, 3% (n = 175) turned positive on RT-PCR while 97% (n = 5925) of the results were consistently negative. The cycle threshold (Ct) values of the false-negative samples (n = 175) showed 90% (n = 158) of them with relatively low viral loads (Ct ≥ 30) with median Ct value at 35, while a number of samples (n = 17) had low Ct values (Ct < 30) and no clear explanation for false-negative results. Our study demonstrates that the Abbott ID NOW, despite it's sensitivity limitations, was capable of providing near real-time results for 10% of symptomatic patients presenting to the ED allowing for improved management and workflow. However, our study findings emphasize the need to reflex negative specimens to a higher sensitivity method when prevalence is high and false-negative results are intolerable.

Non-prescription Fentanyl Positive Toxicology: Prevalence, Positive Predictive Value of Fentanyl Immunoassay Screening, and Description of Co-substance Use.

OBJECTIVES: Opioid overdose deaths in Massachusetts linked to illicitly-manufactured fentanyl have increased dramatically. In response, an urban safety-net hospital added urine fentanyl testing with reflex confirmation testing to its standard urine toxicology panel. The goals of this study were to describe fentanyl toxicology test results, identify the positive predictive value of presumptive fentanyl immunoassay, and describe co-substance use among those with unexpected fentanyl positive results. METHODS: We included urine toxicology tests from January through June 2016 analyzed at an urban safety-net hospital. We excluded tests from individuals prescribed or administered fentanyl within the preceding 72 hours. Positive fentanyl immunoassay tests underwent reflex chromatography confirmation testing. Samples that confirmed positive for acetyl fentanyl and/or fentanyl and/or norfentanyl were considered true positives. RESULTS: Of 11,873 urine samples, 10.4% of samples screened fentanyl positive and 8.8% were confirmed fentanyl positive. The positive predictive value of a positive urine fentanyl screen was 85.7%. Of 4398 unique patients, 13.2% had at least 1 test confirmed positive for nonprescription fentanyl. Patients with a confirmed fentanyl positive drug test were more likely to have positive urine drug test for barbiturates, benzodiazepines, cocaine, methadone, and opiates, and less likely to have oxycodone or buprenorphine. CONCLUSIONS: At an urban safety-net hospital, nonprescription fentanyl use was common and was associated with greater use of other substances favoring routine fentanyl testing. Although the positive predictive value of the screening test was high, confirmation testing detected substantial numbers of false positives, especially in older patients. Therefore, fentanyl confirmation testing should be used when results will change treatment approach and patient education.

A retrospective analysis reveals a predictor of survival for the patient with paraquat intoxication.

Feasible and accurate predictors are urgently needed to evaluate the survival for patients with paraquat poisoning since the high mortality of paraquat poisoning always resulted in the loss of both life and money. Multiple predictors have been developed to predict prognosis of the patients with PQ poisoning, which however heavily depend on the time of admission to hospitals. Here we reported a feasible and accurate prognosis predictor for patients with paraquat poisoning that is independent of the time of admission to hospitals. Patients with paraquat poisoning were enrolled in this study according to the inclusion and exclusion criteria, which were grouped into survivors and non-survivors based on the 90-days follow-up investigation. The concentration of paraquat in serum and urine, and the baseline clinical parameters associated with the injuries of the liver, kidney, and lung were evaluated to predict the survival of these patients by using receiver operating characteristic curve (ROC) analysis, univariate and multivariate cox regression analyses. A total of 114 patients was included in this study with a survival rate of 54.4%. The median survival days of non-survivors were 6.0 (95%Cl: 4.0-7.8). A new predictor, namely paraquat concentration-associated multiorgan injury index (PCAMII), was established by integrating serum and urine paraquat concentration, serum creatinine, alanine aminotransferase, aspartate transaminase, total and direct bilirubin, at different weighting coefficients, with the accuracy of about 90%. The model to predict the survival probability by PCAMII was established with good fitness (R2 = 0.9325), providing the simulated survival rates comparable to the clinical data. PCAMII, which is independent of hospital admission time, is a feasible and accurate marker to predict the survival rate of patients with PQ poisoning.

Comparison of bicarbonate values from venous blood gas and chemistry panels measured at the time of diagnosis and resolution of diabetes ketoacidosis.

OBJECTIVE: To determine if bicarbonate values from venous blood gas (VBG) and plasma chemistry samples provided agreement in determining the bicarbonate criteria for the diagnosis and/or resolution of diabetic ketoacidosis (DKA). METHODS: A retrospective chart review of data from patients admitted to a tertiary care hospital with a diagnosis of DKA over a four year period was performed. Paired bicarbonate values from a VBG and chemistry panel, if drawn within 60 minutes of each other, were compared. RESULTS: At the time of diagnosis of DKA, 197 paired bicarbonate values were available for analysis with the mean difference between the two methods of testing of 2.5 mmol/L. 16 of the 197 (8%) paired values were discordant in meeting criteria for diagnosis of DKA. At the time of resolution of DKA, 83 paired bicarbonate samples were compared. The mean difference was 2.3 mmol/L. 20 of the 83 (24%) paired bicarbonate values showed discordance with regards to meeting the bicarbonate criteria for resolution of DKA. CONCLUSION: Discordance between bicarbonate results from different analysis methods may lead to different determinations as to whether or not a patient meets the biochemical definition for diagnosis and resolution of DKA.

Effect of hemolysis, icterus, and lipemia on three acetaminophen assays: Potential medical consequences of false positive results.

BACKGROUND: We evaluated the effect of hemolysis, icterus and lipemia on 3 acetaminophen assays: namely the Syva® EMIT®, the Microgenics DRI® assay, and the Roche assay on a Roche Cobas® c501 or an Integra 800 analyzer. METHODS: Discarded acetaminophen - free serum samples (blank pool) and patient serum with acetaminophen overdose were used to prepare samples. Three levels of acetaminophen (5, 10, and 30 µg/ml) were evaluated for interference: hemolysis (H index range: 0-1000), icterus (I index range: 0-40), and lipemia (L index range: 0-1000). RESULTS: Measurements showed that the EMIT® assay was not significantly affected by hemolysis or icterus at all 3concentrations evaluated, but was negatively affected by lipemia at all three levels at 1000 mg/dl intralipids. The DRI® assay was similarly affected by hemolysis and icterus, but lipemia (at 1000 mg/dl intralipids) only affected the 5 µg/ml level. The Roche acetaminophen assay was significantly affected by hemolysis at all three concentrations. It was significantly affected by icterus at 20 mg/dl bilirubin and > 5 µg/ml and at icterus levels of 30 and 40 mg/dl bilirubin at 10 and 30 µg/ml acetaminophen concentrations, respectively. However, the Roche assay was least affected by lipemia. CONCLUSION: Hemolysis and icterus had insignificant interference on the Syva EMIT® and the DRI® assays for the analysis of acetaminophen, but significant interference effect on the Roche assay. On the other hand lipemia interfered less markedly with the Roche assay. The effect of hemolysis, icterus and lipemia should always be considered. Cautions are warranted when interpreting results for the potential false positive results in the presence of hemolysis and icterus at the concentrations evaluated in this study.

Association of Biotin Ingestion With Performance of Hormone and Nonhormone Assays in Healthy Adults.

Importance: Biotinylated antibodies and analogues, with their strong binding to streptavidin, are used in many clinical laboratory tests. Excess biotin in blood due to supplemental biotin ingestion may affect biotin-streptavidin binding, leading to potential clinical misinterpretation. However, the degree of interference remains undefined in healthy adults. Objective: To assess performance of specific biotinylated immunoassays after 7 days of ingesting 10 mg/d of biotin, a dose common in over-the-counter supplements for healthy adults. Design, Setting, and Participants: Nonrandomized crossover trial involving 6 healthy adults who were treated at an academic medical center research laboratory. Exposure: Administration of 10 mg/d of biotin supplementation for 7 days. Main Outcomes and Measures: Analyte concentrations were compared with baseline (day 0) measures on the seventh day of biotin treatment and 7 days after treatment had stopped (day 14). The 11 analytes included 9 hormones (ie, thyroid-stimulating hormone, total thyroxine, total triiodothyronine, free thyroxine, free triiodothyronine, parathyroid hormone, prolactin, N-terminal pro-brain natriuretic peptide, 25-hydroxyvitamin D) and 2 nonhormones (prostate-specific antigen and ferritin). A total of 37 immunoassays for the 11 analytes were evaluated on 4 diagnostic systems, including 23 assays that incorporated biotin and streptavidin components and 14 assays that did not include biotin and streptavidin components and served as negative controls. Results: Among the 2 women and 4 men (mean age, 38 years [range, 31-45 years]) who took 10 mg/d of biotin for 7 days, biotin ingestion-associated interference was found in 9 of the 23 (39%) biotinylated assays compared with none of the 14 nonbiotinylated assays (P = .007). Results from 5 of 8 biotinylated (63%) competitive immunoassays tested falsely high and results from 4 out of 15 (27%) biotinylated sandwich immunoassays tested falsely low. Conclusions and Relevance: In this preliminary study of 6 healthy adult participants and 11 hormone and nonhormone analytes measured by 37 immunoassays, ingesting 10 mg/d of biotin for 1 week was associated with potentially clinically important assay interference in some but not all biotinylated assays studied. These findings should be considered for patients taking biotin supplements before ordering blood tests or when interpreting results. Trial Registration: clinicaltrials.gov Identifier: NCT03034707.

Diagnosing sepsis - The role of laboratory medicine.

Sepsis is the host response to microbial pathogens resulting in significant morbidity and mortality. An accurate and timely diagnosis of sepsis allows prompt and appropriate treatment. This review discusses laboratory testing for sepsis because differentiating systemic inflammation from infection is challenging. Procalcitonin (PCT) is currently an FDA approved test to aid in the diagnosis of sepsis but with questionable efficacy. However, studies support the use of PCT for antibiotic de-escalation. Serial lactate measurements have been recommended for monitoring treatment efficacy as part of sepsis bundles. The 2016 sepsis consensus definitions include lactate concentrations >2mmol/L (>18mg/dL) as part of the definition of septic shock. Also included in the 2016 definitions are measuring bilirubin and creatinine to determine progression of organ failure indicating worse prognosis. Hematologic parameters, including a simple white blood cell count and differential, are frequently part of the initial sepsis diagnostic protocols. Several new biomarkers have been proposed to diagnose sepsis or to predict mortality, but they currently lack sufficient sensitivity and specificity to be considered as stand-alone testing. If sepsis is suspected, new technologies and microbiologic assays allow rapid and specific identification of pathogens. In 2016 there is no single laboratory test that accurately diagnoses sepsis.

The volume ratio of ground glass opacity in early lung CT predicts mortality in acute paraquat poisoning.

BACKGROUND: Pulmonary injury is the main cause of death in acute paraquat (PQ) poisoning. However, whether quantitative lung computed tomography (CT) can be useful in predicting the outcome of PQ poisoning remains unknown. We aimed to identify early findings of quantitative lung CT as predictors of outcome in acute PQ poisoning. METHODS: Lung CT scanning (64-slide) and quantitative CT lesions were prospectively measured for patients after PQ intoxication within 5 days. The study outcome was mortality during 90 days follow-up. Survival curves were derived by the Kaplan-Meier method, and mortality risk factors were analyzed by the forward stepwise Cox regression analysis. RESULTS: Of 97 patients, 41 (42.3%) died. Among the eight different types of lung CT findings which appeared in the first 5-day of PQ intoxication, four ones discriminated between survivors and non-survivors including ground glass opacity (GGO), consolidation, pneumomediastinum and "no obvious lesion". With a cutoff value of 10.8%, sensitivity of 85.4% and specificity of 89.3%, GGO volume ratio is better than adopted outcome indicators in predicting mortality, such as estimated amount of PQ ingestion, plasma or urine PQ concentration, acute physiology and chronic health evaluation (APACHE) II and sequential organ failure assessment (SOFA) scores. GGO volume ratios above 10.8% were associated with increased mortality (hazard ratio, 5.82; 95% confidence interval, 4.77-7.09; P < 0.001). CONCLUSIONS: The volume ratio of GGO exceeding 10.8% is a novel, reliable and independent predictors of outcome in acute PQ poisoning.

Effect of two different FDA-approved D-dimer assays on resource utilization in the emergency department.

BACKGROUND: The D-dimer assay has been shown to be an appropriate test to rule out pulmonary embolism (PE) in low-risk patients in the emergency department (ED). Multiple assays now are approved to measure D-dimer levels. Studies have shown a newer assay, Tina-quant, to have similar diagnostic accuracy to the VIDAS assay. OBJECTIVES: The objective was to determine effects of transitioning from the VIDAS assay to the Tina-quant D-dimer assay on the need for computed tomography angiogram (CTA) and ED length of stay (LOS) in patients being evaluated for PE in the ED. METHODS: A retrospective cohort study was conducted of patients who had D-dimer levels ordered at an urban, academic, Level I trauma center with over 55,000 annual ED visits. The results of D-dimer levels in the ED were recorded over a period of 6 months prior to and 6 months after the transition to the new D-dimer assay. The numbers of positive and negative D-dimers and need for subsequent CTAs were recorded for comparison. LOS was also recorded to determine time saved. Medians were calculated and compared using Wilcoxon rank sum. RESULTS: During the initial period, 875 D-dimers were ordered, with a positive rate of 41.5%. During the period after the introduction of the Tina-quant assay, 859 tests were ordered, with 25.5% having positive results. An absolute decrease of 16% in the number of necessary CTAs (p < 0.003) was seen after the transition to the Tina-quant assay. LOS data showed a mean LOS of 481 minutes in the ED for patients who underwent testing with the Tina-quant assay compared to 526 minutes with the VIDAS assay, saving an average of 45 minutes per patient (p < 0.003). The positive rate on performed imaging studies for D-dimer of > 500 rose from 13 of 308 (4.2%) to 17 of 187 (9.1%). CONCLUSIONS: Switching D-dimer assays reduced both LOS and number of imaging studies in our patient population.