bluuebunny/crossref_metadata_2025 huggingface dataset:
A-288 Molecular Detection of Mycobacterium tuberculosis in Pulmonary and Extra-Pulmonary Samples. Data from a Brazilian Clinical Laboratory
Authors: Nurmberger J M , de Carvalho G C , Perez B B , Santos M N , Ramadan D R , Tufik S
Published: September 2023

Background

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), is among the leading infectious causes of death in developing countries. In humans, TB presents as a progressive granulomatous infectious disease that affects lungs causing pulmonary tuberculosis, but can also affect intestines, meninges, bones, joints, lymph nodes, skin and other body tissues causing extra-pulmonary tuberculosis. The aim of this study was to evaluate the frequency of tuberculosis cases detected during the COVID-19 period and the emergence of cases with extrapulmonary diagnosis.

Methods

This study was a retrospective analysis from January 2017 to December 2022 based on the analysis of 3105 clinical samples processed by the molecular biology section of AFIP Laboratory. All clinical samples were isolated from pulmonary and extra-pulmonary sites recovered from inpatients admitted in several Brazilian tertiary hospitals. In Brief, the DNA extraction was performed according to the type of patient’s samples and, then submitted to Real-Time PCR (qPCR) method using a commercial kit, which contains specific primers and probes to the M. tuberculosis genome.

Results

Of the 3105 samples tested, 222 (14%) samples were positive for the presence of M. tuberculosis. Out of which, 120/1405 (8,5%) were detected in the pre-Covid-19 period (2017–2019) and 102/1700 (6%) were detected in Covid-19 period (2020–2022). The prevalence of M. tuberculosis infection was 64.5% and 35.5% among men and females, respectively. The main age range was 41 to 50 years (44.7%), while over 60 years comprised 13.5% of cases (Fig. 1). Between the isolate sites, 67.1% of the M. tuberculosis cases were detected in pulmonary and 32.8% in extra-pulmonary body sites, of which, cerebrospinal fluid and blood are among the most frequent, followed by cervical lymph node, ascitic fluid, gastric lavage, urine and others. A total of 95% of M. tuberculosis was detected in patients assisted by public health service. We did not have access to patient’s symptoms, clinical history or further diagnostic procedures.

Conclusion

Comparing the two periods of the study, a reduction in the positivity rate of new cases was observed in the pandemic period, perhaps this fact can be associated with restrictions on access to the diagnosis of other pathologies in the pandemic period. Despite no information about the severity of the infection, male gender prevalence and age range from 41 to 50 years group need further attention.
A-295 Validation of Two New Real Time PCR Assays for the Detection and Differentiation of Plasmodium
Authors: Cisteró P , Franco-Marín E , Dehesa-García B , García-Manrique B , Alonso H , Matambisso G , Mbeve H , Ndimande N , Mayor A
Published: September 2023

Background

Malaria (or paludism), the mosquito-borne parasitic disease caused by Plasmodium, is a major global public health threat among communicable diseases. The objective of this study was to determine the clinical performance of VIASURE Malaria Real Time PCR Detection Kit and VIASURE Malaria differentiation Real Time PCR Detection Kit using dried blood spot on filter paper samples.The aim of this retrospective study was to validate and compare the clinical sensitivity and specificity of the VIASURE assays with the reference method used in the laboratory.

Methods

The Malaria assay, which detects the genus Plasmodium spp. and the differentiation assay, which distinguishes the main human pathogenic Plasmodium species: P. falciparum, P. ovale, P. vivax, P. malariae and P. knowlesi, were used in comparison with an 18S rRNA in-house malaria screening and differentiation assays. A total of 300 blood on filter paper collected from 2016 to 2019, from patients with clinical suspicion of malaria in the Manhiça-Magude district of southern Mozambique were analysed. The DNA extraction was carried out using the Chelex® 100 sodium method and the thermocycler employed was Applied Biosystems 7500 Real-Time PCR System.

Results

A total of 77 samples were considered as Plasmodium spp.-positive by both assays, 1 false positive result and 15 false negative results for VIASURE were obtained and 207 samples showed to be negative for this target by both assays. Regarding species differentiation: VIASURE assay showed 58 true positive and 3 false negative results for P. falciparum, 2 true positive results for P. malariae and 1 true positive and 1 false negative result for P. ovale. After data analysis, the sensitivity and specificity values obtained were:

Conclusion

This retrospective study demonstrated the good sensibility and specificity of both VIASURE molecular assays using this extraction method on dried blood spots.
A-298 Performance Analysis of Three Mpox Real Time PCR Kits With Lesion Swab Clinical Samples
Authors: Peris M , Franco-Marín E , Dehesa-García B , García-Manrique B , Alonso H
Published: September 2023

Background

The appearance of skin lesions can be a symptom of infection or reactivation of the HSV-1, HSV-2, VZV or T. pallidum or even monkeypox virus infection. Due to the contact-bound ease of spread of these pathogens, an accurate and fast diagnosis, such as PCR-based testing, is key to a good epidemiological management. The aim of this study was to determine the clinical performance of three qPCR assays.

Methods

A total of 334 cutaneous swabs collected from patients attended at the Hospital Universitario Miguel Servet were analysed using the three assays under study: VIASURE Herpes virus 1, Herpes virus 2 & Varicella Zoster Virus Real Time PCR Detection Kit, VIASURE Treponema pallidum Real Time PCR Detection Kit and VIASURE Mpox Real Time PCR Detection Kit. Samples were collected between December 2021 and November 2022. These samples were requested through the Biobanco del Sistema de Salud de Aragón (BSSA) and have the approval of the Aragón Ethics Committee (PI22/409). DNA/RNA extraction was performed using the automated extraction method magLEAD® 12gC instrument with the MagDEA Dx SV kit and amplification was performed using the thermocycler CFX96™ Real-Time PCR Detection System (BioRad). The obtained results were compared with the reference assays RealStar® Orthopoxvirus PCR Kit 1.0 (Altona) and Allplex™ Genital ulcer assay (Seegene®).

Results

After data analysis a very good overall agreement was obtained for all the studied targets.

Conclusion

The assays under study demonstrated to be a good tool for differential analysis in skin lesions compatible with HSV-1, HSV-2, VZV, T. pallidum or mpox virus infection. In addition, the shared thermal protocol of the assays allowed for the simultaneous detection in the sample, creating a personalized panel option for the user, as opposed to the reference assays employed, which required two separate analyses, taking longer to reach the full assessment of the sample.
A-299 Clinical Performance Validation of 7 qPCR Kits for the Specific Diagnosis of 5 Enteric Viruses in Clinical Stool Samples
Authors: Costafreda M , Bosch A , Pintó R M , Dehesa-García B , García-Manrique B , Alonso H , Guix S
Published: September 2023

Background

Among the most prevalent enteric viruses associated with gastroenteritis are norovirus (NoV), rotavirus (RV), astrovirus (AstV), sapovirus (SaV) and adenovirus (AdV). The diagnosis of infections associated with gastroenteritis viruses is mainly based on the detection of the genome of these viruses by molecular methods, mainly qPCR and RTqPCR reactions. The aim of this study was to validate the diagnostic performance of 7 qPCR diagnostic kits of the “VIASURE Real Time PCR Detection Kits” series with respect to commercial reference kits used for the diagnosis of these pathogens.

Methods

A total of 318 clinical stool samples were used, including: 213 stool samples from children from sporadic cases of gastroenteritis collected between 2016–2018; 94 samples from outbreaks of gastroenteritis caused by NoV between 2017–2019; and 11 samples from healthy children with asymptomatic enteric virus infections collected between 2017–2018. Seven VIASURE kits were used for the specific detection of enteric viruses. At the same time, samples were also tested with the following commercial kits used as reference methods: RIDA®GENE Viral Stool Panel II (rotavirus, adenovirus 40/41 and astrovirus) and RIDA®GENE Sapovirus, RIDA®GENE Norovirus I & II. In the case of AdV, the positivity of the samples was confirmed using the qPCR protocol published by Heim et al. (2003).

Results

The results obtained are summarized in Table 1.

Conclusion

The results obtained show a high sensitivity and specificity of the VIASURE kits for the detection of rotavirus, adenovirus, sapovirus, astrovirus and norovirus GI and GII (in the latter case using both the monoplex and multiplex product). In addition, it should be noted that all these kits share the same thermal protocol, thus allowing their joint use for the simultaneous diagnosis of these 5 enteric viruses.
A-312 Segregation in Two Families of the PCDH19Gene Deletion Associated With Infantile Epileptic Encephalopathy of X-Linked Inheritance and Expression in Female Carriers
Authors: Bellido Diaz M , De haro Romero T , Gonzalez T , de Haro T
Published: September 2023

Background

Developmental and epileptic encephalopathy-9 (DEE9) is an X-linked disorder characterized by seizure onset in infancy and mild to severe intellectual impairment. Autistic and psychiatric features have been reported in some individuals. The disorder affects heterozygous females only; transmitting males are unaffected. We described the segregation in two unrelated families where the proband was clinically affected as a female and another family where the proband was clinically unaffected as a male.

Methods

Array-CGH analysis was performed by a CGXTM HD v1,1 4-plex array 180 k (PerkinElmer), with an average resolution of 40 kb in the backbone and 20 kb in the regions of interest.

Results

In the first family a deletion of 809.93 Kilobases was detected in the chromosomal region Xq22.1, which includes the PCDH19 gene, in a 1 year old patient with very early onset seizures, 8 months old, inherited from an asymptomatic father. In the second family, a deletion that includes the entire PCDH19 gene was detected in a 5-year-old male patient referred to genetics for autism spectrum disorder (ASD) and not symptomatic for epilepsy; this deletion was inherited from a mother who had episodes of epilepsy in childhood.

Conclusion

The aCGH technique is currently the technique of choice to determine the presence of deletions/duplications in genes of interest with high reliability in patients with neurodevelopmental disorders such as epilepsy or ASD. The probands of these two families have been studied for different clinical pathology and in both the deletion of the complete PCDH19 gene has been detected.

The PCDH19 gene is expressed in developing human and mouse central nervous system, including the hippocampus and cortex, suggesting a role in cognitive function. Malfunction of the protocadherin19 protein is the cause of epileptic seizures in early childhood, the seizures are mostly focal and cause serial seizures (many seizures that cluster together over a few days). It is a type of epilepsy that usually begins in early childhood. Onset may occur spontaneously or in association with fever. Mutations/deletions of the PCDH19 gene are described to cause Early Childhood Epileptic Encephalopathy, with high but incomplete penetrance. DEE9 affects only females heterozygous for the deletion and is characterised by childhood onset of seizures/epilepsy, usually with mild/severe intellectual disability, with males being healthy carriers. Although the cause is not known specifically, it is thought to be related to X-chromosome silencing that occurs in females heterozygous for this mutation. It causes an autosomal dominant X-linked disorder. Some cases of males with a mosaic PCDH19 mutation/deletion have been found to be affected and it has been suggested that the presence of both the normal gene and the mutated/deleted gene is necessary to develop for this epileptic encephalopathy.
A-327 Pre-analytical and Analytical Modifications to Improve the Quality of Pediatric Lead Tests
Authors: Nassif J , Liebreich J , Granger K
Published: September 2023

Background

The recent decrease in the CDC Blood Lead Reference Value (BLRV) to 3.5 ug/dL has highlighted the need for systematic changes that some clinicians and laboratories need to implement to assure the quality of reported pediatric lead results. Building upon the recommendations of the Blood Lead Reference Value Workgroup, APHL has developed specific recommendations and resources designed to assist medical professionals and laboratory scientists in minimizing the likelihood of contamination when collecting and testing blood specimens. Also included are analytical practices that can improve precision, accuracy, and sensitivity of pediatric lead assays.

Methods

Evaluation of existing protocols and practices to identify potential sources of contamination and opportunities for process improvement.

Results

APHL will provide practical recommendations to systematically improve point of care and fixed laboratory testing to improve confidence in reported pediatric lead concentrations. These improved measurements will improve environmental health surveillance and inform public health intervention and patient care.

Conclusion

Rigorous pre-analytical practices including education, updated specimen collection guidance, pre-screening of collection materials, improvement of point of care technology and refinement of spectroscopic analytical methods result in less ambient contamination, improved sensitivity, precision and accuracy of pediatric lead testing. Clinician office practices, public health and commercial clinical laboratories will all benefit from implementing these strategies.
A-328 Urine Toxicology Screening: Tetrahydrocannabinol Positivity Patterns at an U.S. Urban Tertiary Care Children's Hospital
Authors: Unsihuay Vila D M , Poventud-Fuentes I , Osterhoudt K , Patel K
Published: September 2023

Background

Given the recent legalization of recreational and medical marijuana in different states, there is an increasing exposure of children and teenagers to marijuana products which has led to an increase in health care visits and hospitalizations. Our drug testing algorithm uses an immunoassay test for initial urinary drug screening (UDS) followed by an automatic confirmatory test only when a positive UDS result is obtained. The immunoassay test is performed in-house and detects the major metabolites of delta9- tetrahydrocannabinol (THC), the main psychoactive component of marijuana. In contrast, the liquid chromatography-tandem mass spectrometry (LC-MS/MS) confirmatory test is more specific towards THC and is carried out in an external lab. In light of the ongoing trend of marijuana exposure cases and the fact that immunoassay cross-reactivity with non-cannabinoid compounds is uncommon, we aim to assess the necessity of automatic confirmatory tests in our patient population and evaluate its impact on patient management.

Methods

We conducted a retrospective study to assess the trends in cannabinoid hospital-related encounters by age, gender, and incidence with other drugs, in our population among the main campus and satellites (November 2021–October 2022). The UDS tests that were positive for cannabinoids were further evaluated to assess their agreement with the confirmatory testing.

Results

Cannabinoid positive tests account for 62.0% (504/813) of all positive UDS tests in all our locations and 84% (425/504) of the cases did not test positive for other drug classes. Among this population, 92.7% (467/504) are in the adolescent age (≥13 years), whereas 7.3% (37/504) were children (<13 years). Female population comprises 56.0% (217/504) of the cases whereas male, 43% (271/504) of the cases. The true positive rate for the immunoassay test was 99.6% (465/467) and 94.6% (35/37) for adolescents and children, respectively. Clinical decisions were made after a positive immunoassay result and before the confirmatory test as this is a send out test and takes a few days to receive the result.

Conclusion

Our evidence-based approach demonstrates unnecessary confirmatory testing for the adolescent group in our population due to a high positivity rate (99.6%). Discontinuing automatic confirmatory testing for this group will eliminate workload and reduce healthcare costs. On the other hand, automatic confirmatory testing in children will continue as these exposures are mainly considered unintentional and require more investigation.
A-333 Unusually Low Glycated Albumin Results Suggest Unexpected Interference in Study Samples from Pregnant Women
Authors: Powers Carson J , Shin A , Kabytaev K
Published: September 2023

Background

Glycated albumin (GA) is an alternate marker of glucose control that is recommended in situations when hemoglobin A1c is unreliable. One of us (JPC) has examined its use in pregnant women with diabetes since 2019 and regularly observed GA values of 8.0–19.4%, with occasional outliers. However, in a recently recruited cohort of 149 women with and without gestational diabetes, 58% of the samples showed GA results <8.0%, despite no apparent physiological differences. Here we further investigate a subset of these samples using a liquid chromatography-mass spectrometry method (LC-MS/MS).

Methods

Glycated serum proteins (GSP) were measured using the GlycoGap kit (Diazyme Labs, Poway, CA), an enzymatic method, and subsequently converted to percent glycated albumin (GA%) using the equation provided by the manufacturer.The LC-MS/MS assay was performed according to a previously published protocol. The samples were first reduced and alkylated, then spiked with a blend of two isotope-labeled standards and digested using Glu-C enzyme. The resulting digests were analyzed using the QTRAP 6500+ (AB Sciex, Foster City, CA) coupled with a LC system (Shimadzu, Japan) in MRM mode to provide values representing the percentage of glycated to non-glycated Lys-525 in albumin (MSGA%).Samples from a previously collected cohort (A, n = 78) of pregnant women with and without diabetes, with GA% range of 8.5–24.2%, were analyzed using both methods, and a standard curve (MSGA% vs GA%) was established. Thirty-eight samples with GA <8.0% (cohort B) were then analyzed using the LC-MS/MS method, and the standard curve was used to generate the expected enzymatic GA% results.

Results

The comparison of the LC-MS/MS and Diazyme methods resulted in a straight-line equation (r2 = 0.84, slope = 1.81, y-intercept = 0.79). For the cohort B samples analyzed by LC-MS/MS, the median MSGA% result was 5.89% (range: 4.32–8.95%). Based on the equation derived from the method comparison (MSGA% vs GA%), the expected median value with the Diazyme enzymatic method would have been 11.48% (range: 8.63–17.02%). These GA% values are well within the typically expected range.

Conclusion

LC-MS/MS results and GA% calculated from a method comparison curve were within the expected range while original enzymatic results were not, suggesting the presence of an interfering substance. Our hypothesis is that prenatal supplements may lead to elevated ascorbic acid, which is known to cause interference in certain enzymatic assays. We are continuing to investigate this possibility.
A-359 Performance of Measured TCO2 on the epoc Analyzer
Authors: Evans L M , Dilks M , Goldsmith B M
Published: September 2023

Background

The epoc Blood Analysis System (Siemens, Tarrytown, NY) performs blood gases, electrolytes, and metabolites using a Blood Gas, Electrolyte and Metabolite (BGEM) Test Card on 92 uL of whole blood. The BGEM Test Card uses potentiometric sensors to measure sodium, potassium, chloride, ionized calcium, pH, pCO2; amperometric sensors to measure pO2, glucose, creatinine, and lactate; and a conductometric sensor to measure hematocrit. Results are available in 3–10 minutes, depending upon the time of sample injection. TJUH implemented epoc in its ICUs in 2012 to provide rapid, whole blood Point of Care (POC) results and has expanded to other locations (Emergency Department, Outpatient Radiology, Cardiothoracic Surgery). While previous epoc cards provided calculated TCO2 (cTCO2), Siemens recently added measured TCO2 (mTCO2; combination of potentiometric sensors and calculation) to its BGEM card. We evaluated this card for future use.

Methods

Precision and method comparison studies were performed at our Center City location. Inter- and intra-precision studies were performed on two levels of controls (Eurotrol, Elizabethtown, KY). Whole blood was collected in heparinized syringes from 20 patients. Comparison studies were performed on the ABL800 (Radiometer, Brea, CA). We simultaneously compared epoc mTCO2 against epoc cTCO2 and against the cTCO2 on the ABL800.

Results

Intra-assay precision for epoc mTCO2 (n = 20, 2 devices) was 0.8%CV and 2.3%CV for Levels 1 and 3, respectively. Inter-assay precision for epoc mTCO2 (n = 20, 2 devices over 10 days) was 1.1%CV and 3.3%CV for Levels 1 and 3, respectively. Method comparison for epoc mTCO2 (n = 20) was: mean = 22.9, median = 22.1, r2 = 0.9174, y = 0.9751x + 1.2925. In comparison, method comparison for epoc cTCO2 (n = 20) was: mean = 24.7, median = 23.9, r2 = 0.9165 y = 0.9855x + 2.8559.

Conclusion

The epoc measured TCO2 studies show better correlation to the Radiometer ABL800 than the epoc calculated cTCO2, and it is considered acceptable for implementation at our Center City sites where epoc is currently in use.
A-368 Aspergillus Galactomannan Lateral Flow Assay with Digital Reader for the Diagnosis of Invasive Aspergillosis
Authors: Peng J , Yan J , Du J , Wang Y , Wang H , Su Y , Zhou Z
Published: September 2023

Background

The Novel Aspergillus Galactomannan Lateral Flow Assay(Quic GM) from Dynamiker Biotechnology (Tianjin) Co., Ltd is a fluorescent immunochromatographic cassette test using a monoclonal antibody against GM with Digital Reader (Figure 1), which was rapid and easy to operate compared with the traditional GM ELISA assay. Here we conducte a comparative study between the Dynamiker Quic GM and the Platelia GM (Bio-Rad, USA) to validate the performance of the novel assay for the diagnosis of Invasive Aspergillosis (IA).

Methods

A total of 573 serum samples and 97 BALF samples with proven IA (Serum n = 9, BALF n = 2), probable IA (Serum n = 174, BALF n = 25), possible IA (Serum n = 98, BALF n = 16) and patients not fulfilling 2019 EORTC/MSG guideline IA criteria (control, Serum n = 292, BALF n = 54) were included. All the samples were tested in parallel using the Quic GM and Platelia GM.

Results

The total coincidence rate of Quic GM compared with Platelia GM was 97.91% (Kappa value was 0.95 > 0.75), 97.94% (Kappa value was 0.95 > 0.75) and 97.91% (Kappa value was 0.95 > 0.75) in serum samples, BALF samples and serum+BALF samples, respectively (Table 1). The concentrations generated by Quic GM and Platelia GM were linearly correlated (Serum: slope = 0.97, r2 = 0.96, P < 0.0001; BALF: slope = 0.95, r2 = 0.94, P < 0.0001) (Figure 2).

Conclusion

In conclusion, the Dynamiker Quic GM yielded significant consistency with Bio-Rad Platelia GM ELISA, and showed good performances for IA diagnosis, with the benefit of a relatively short handling time (around 20 min).
A-374 Analytical Performance Assessment and Comparison of Point of Care Testing (POCT) Devices for Blood Lipids Measurements
Authors: Dahya K , Pokuah F , Danilenko U , Vesper H W
Published: September 2023

Background

Cardiovascular diseases (CVDs) are the leading cause of death in the U.S. and worldwide. According to the World Health Organization (WHO), worldwide, 85% of CVD deaths are due to heart disease and strokes, and over 75% occur in low- and middle-income countries (LMICs). Early detection and treatment are key to preventing the consequences of CVD. Point-of-care testing (POCT) devices offer alternatives to screening large populations for CVD risk. Although POCT are increasingly used for screening, only few information is available about their accuracy and reliability.

Methods

Eight POCT devices for blood lipids that previously successfully participated in the CDC CVD Biomarker Standardization Programs were used in this preliminary study. The analytical performance for all eight devices was assessed using split sample comparisons to the CDC reference measurement procedures for measurements performed in whole blood (WB) and serum. Specifically, the accuracy of total cholesterol (TC) was determined in WB and serum. The accuracy of high-density lipoprotein-cholesterol (HDL-c), and low-density lipoprotein-cholesterol (LDL-c) was determined in serum. The precision of TC, HDL-c, LDL-c, and triglycerides (TG) was determined in WB and serum.

Results

The reference values of the specimens from 20 donors ranged between 154–279 mg/dL, 36.9–109 mg/dL, and 71.1–182 mg/dL for TC, HDL-c, and LDL-c in serum, and between 145–210 mg/dL for TC in WB. Preliminary assessments found that the mean bias for each instrument ranged from -7.86%–13.82% and from -11.90%–3.24% for TC in WB and serum, respectively. For serum HDL-c samples, the mean bias ranged from −6.81%–15.43%. The mean bias for serum LDL-c samples ranged from −22.40% to 3.08%. For three devices, approximately 30% of the WB measurements and approximately 50% of the serum measurements were reported as outside of the measurement range. The mean imprecision for each instrument ranged from 2.2%–13.75% and from 1.88%–11.76% for TC in WB and serum, respectively. For HDL-c, the mean imprecision ranged from 5.36%–23.21% and from 2.30% to 26.69% in WB and serum, respectively. The mean imprecision ranged from 4.82%–20.34% and from 3.06%–20.54% for LDL-c in WB and serum, respectively. For TG, the mean imprecision ranged from 5.78%–23.91% and from 1.71%–11.02% in WB and serum, respectively.

Conclusion

These preliminary findings about the analytical performance of POCT devices indicate notable differences in accuracy and precision for lipids measured in WB and serum, with serum measurements being more likely within performance requirements than WB measurements. Some devices appear to be more likely to report values outside the measurement range even though reference values are within the measurement range of the device. Further studies to verify these preliminary findings with more individual donor samples are underway.
A-375 Evaluation of the CLIA-Waived Afinion HbA1c Point-of-Care Test
Authors: Villasin E , Metushi I
Published: September 2023

Background

Point-of-care (POC) HbA1c tests can be essential in evaluation/monitoring of diabetes provided that the test has acceptable analytical performance. The Abbott Afinion HbA1c is an in vitro diagnostic test for quantification of HbA1c in human capillary and venous whole blood. This study aim was to evaluate the performance of Afinion HbA1c in whole blood EDTA patient samples.

Methods

The Afinion utilizes the boronate affinity principle for measurement of HbA1c. Hemoglobin A1c was tested on the Abbott AfinionTM 2 analyzer. Two levels of quality control (QC) and two levels of whole blood EDTA patient samples (one low and on high) were used to assess imprecision. Within-day precision was determined by assaying the 20 times in one day and between-day precision was determined by assaying the samples in duplicates over a period of 10 days. The analytical measured range (AMR) and method comparison was performed by using whole blood EDTA patient samples. Percent bias plot and Deming regression analysis was performed by EP Evaluator.

Results

Within-day and between-day precision and accuracy data are summarized in table 1 below. The assay displayed good linearity over the measured AMR. Lastly, the method comparison between Afinion vs Cobas pro, had a correlation coefficient R2 of 0.994, slope (m) of 1.14 and % bias was 2.5%. Afinion vs Trinity Biotech HPLC had R2 = 0.996, m = 1.04 and % bias was −2.3%. Afinion vs DCA Vantage had R2 = 0.991, m = 1.03 and % bias 1.5.

Conclusion

We conclude that the Abbott Afinion POC device evaluated here is precise and yields results consistent with other Clinical Chemistry analyzers such as Cobas Pro and Trinity Biotech.
A-378 Clinical Evaluation and Implementation of Rapid COVID-19 Antigen Test in Qatar
Authors: Said J S , Afreen F , Al-Wali D , Al Kuwari E A , Kabir Z M , Salem A M
Published: September 2023

Background

In March, the World Health Organization (WHO) declared COVID-19 as a global public health emergency. To curb the spread of virus, timely detection of infected patients and screening of suspected cases in massive population posed a challenge for the healthcare system. Rapid antigen tests (RAT) were high in demand as a fast, accurate and cost-effective screening tool to increasing the testing capacity. In this crucial timing, clinical evaluation and procurement of available COVID-19 RAT following the World Health Organization (WHO) guidelines was a huge challenge for Point of Care testing (POCT) department. The aim of this study is to highlight the challenges overcame in establishing a Point-of-care COVID-19 testing system including personnel training and building a compatible Laboratory Information System (LIS) upholding Hamad Medical Corporation (HMC) cyber security regulation.

Methods

Three regulatory approved RATs were evaluated against real-time polymerase chain reaction (RT-PCR) and analytical performance were verified. Maintaining the Clinical Laboratory Improvement Amendments (CLIA) and College of American Pathologist (CAP) standards for COVID-19 waived testing, POCT team initiated to conduct practical and educational training vastly through online platforms and face to face sessions. We utilized the extendable LIS functionality for fast medical decisions in hospitals and enabled “reason of testing” feature in Qatar's COVID-19 tracking application.

Results

Our performance verification showed 98.0% sensitivity and 100% specificity for PanbioTM COVID-19 RAT, 98.0% sensitivity and 100% specificity for Quidel SOFIA2 COVID-19 RAT and Roche COVID-19 RAT yielded a sensitivity of 97.0% and specificity of 100%. Total of 291 training sessions were conducted for 9710 clinical staffs across 17 HMC facilities and 185 private clinics. Using LIS and POC middleware features, obvious increment in RAT of more than 509 tests per day has been reported in a single emergency unit. Overall, 5.5% decrement in incorrect patient identification data using QUIDEL SOFIA2 automated device and LIS functions was recorded in laboratory quality indicator data. COVID-19 tracking application was linked to antigen results for contact tracing, isolating, and breaking the chain of transmission.

Conclusion

The methods established for the COVID-19 implementation showed acceptable performance fulfilling the elements of HMC product procurement specification and CAP Accreditation standards. Synergic actions of HMC-POCT with supportive laboratory management aided prompt decision making to optimize patient management and added efficiency to the public health control measures in Qatar.
B-009 Accuracy Validation of Elecsys HBsAg II Quant Assay to Resolve Equivocal Qualitative HBsAg Results
Authors: Kim D , Lee J , Park J , Kim N , Lee S , Cho Y
Published: September 2023

Background

There are reports of false qualitative HBsAg results because of several causes, such as samples with low HBsAg concentrations that may produce false positives. The main aims of this study are to validate the analytical accuracy and operational cutoff value of the Elecsys HBsAg II Quant assay. The secondary goal is to assess the role of the Elecsys assay in resolving equivocal quali-tative HBsAg results compared to those of the qualitative HBsAg assay in the medical laboratory.

Methods

The limit of blank (LoB), limit of detection (LOD), limit of quantification (LoQ), and linearity were first estimated to validate the analytical accuracy of the Elecsys HBsAg II Quant assay. To validate the linearity of the assay according to CLSI EP06-A, five expected diluted as-sayed samples, including 0.01 (dilution ratio of minimum to maximum value = 4:0), 11.90 (3:1), 23.70 (2:2), 35.50 (1:3), and 47.30 IU/mL (0:4), were prepared within the concentration of the WHO 3rd IS (47.3 IU/mL) and measured for five replicates at each level. A total of 449 serum samples showing initial equivocal results (1–50 index) were evaluated by El-ecsys HBsAg II Quant and ADVIA Centaur HBsAg II assays.

Results

The LoQ of the assay was determined to be 0.050 IU/mL, as provided by the manufacturer. The Kappa agreement between the two assays was almost perfect at 0.9669 despite the seven dis-cordant results. The ROC curve analysis of this assay showed an AUC of 0.965 (P < 0.001), with a specificity of 100% and sensitivity of 24.15% at the new COI value of 5.42. Those HBsAg samples with index values <5.42 need to be confirmed with an approved method or via additional HBV marker assays without further duplicate tests. The Kappa agreement between the two assays was almost perfect at 0.9669 despite the seven discordant results (three by ADVIA Centaur HBsAg II Negative and Elecsys HBsAg II Quant Positive; four by ADVIA Centaur HBsAg II Positive and Elecsys HBsAg II Quant Negative). The concordance rate and accuracy of the ADVIA Centaur HBsAg II as-say relative to the Elecsys HBsAg II Quant assay from the confirmed results were 98.44% and 98.55%, respectively, when the HBsAg seroprevalence of 5.3% from the Western Pa-cific region, including South Korea, was applied.

Conclusion

We confirm that the Elecsys HBsAg II Quant assay is a very accurate and sensitive for HBV infec-tion and recommend it as an alternative confirmatory HBsAg assay for resolving equivocal qualitative HBsAg results.
B-013 Association Between Laboratory Parameters Analysis and Clinical Severity in Patients With Coronavirus Disease (Covid 19) at Hospital Universitario Fundación Santa Fe
Authors: Martinez Nieto O , Gonzalez H A , Saavedra Andrade C E , Bertel Rodriguez D M , Rodriguez Urrego P A , Vargas Gallo J P
Published: September 2023

Background

Clinical management of COVID-19 disease was challenging. Laboratory parameters could be useful to classify patients in risk scores and probability to progress to a severe stage at the emergency room. This study aims to determine the association between laboratory parameters of COVID-19 patients and clinical disease severity to provide applicable information to improved treatment strategies. Thus, we described the laboratory findings that can work as a predictive marker of severity, in a cohort of patients form our institution from Colombia diagnosticated with COVID-19 during a period of one year.

Methods

This retrospective cohort descriptive study was conducted at one quaternary hospital at Bogota Colombia, where laboratory parameters on peripheric blood samples in 298participants with COVID-19 diagnosis were evaluated. For comparison between two groups’ data, the chi-square and Mann-Whitney U test were used. For correlation between variable a Spearman and a Kruskal Wallis test were performed as data didn’t normal distribution. A P-value lower than 0.05 was considered statistically significant in all analyses.

Results

Primary outcomes shown significant correlation between more severe disease and interleukin IL-6 elevation, by the Kruskal Wallis test. Lower counts of lymphocytes percent, ferritin, fibrinogen, neutrophils, basophils and coagulation factors were found to be associated with severe disease (P < 0.0001). Creatinine, D dimer, LDH, WBC count, creatinine and erythrosedimentation were significantly higher and were correlated with more severe disease on scores (P < 0.001). Higher levels on PCR parameters were associated with severe disease (P < 0.001).

Conclusion

Laboratory parameters such as IL-6 can be used as a severity marker in order to help physicians find both adequate treatment and hospitalization location of COVID-19 patients. This information can be used to manage future pandemics, and to evaluate complementary strategies that should be efficient on epidemic management and patient care having an impact on public health, mortality rates and hospitality capacity
B-027 Adaptation of Neonatal Dried Blood Spot Assays for Use on Automated Microplate Instruments
Authors: Van Slooten G
Published: September 2023

Background

Newborn screening (NBS) is routinely conducted to identify various inherited metabolic disorders which can affect a child’s long-term health or survival. The assay methods used include enzyme-linked immunosorbent assays (ELISA) as well as enzymatic biochemical assays. Dried blood spots (DBS) prepared by applying whole blood to filter paper cards are typically used as the sample for these screening assays. In this study we have adapted an openly programmable automated ELISA processing instrument to perform these types of assays with a high level of accuracy and precision.

Method

The Awareness Technology (Palm City, FL) ChemWell-2 instrument was chosen for this study. This instrument is a two plate ELISA processing system which has the capability of performing the DBS extraction in an uncoated round bottom 96-well microplate and transferring a small volume of extracted sample to be assayed to a second flat bottom 96-well microplate. The following enzymatic assay kits manufactured by ZenTech (Liège, Belgium) were used in this study: total galactose, phenylalanine, glucose-6-phosphate dehydrogenase (G-6-PD) and biotinidase.

Results

In order to evaluate the assay performance controls and additional standard DBS were run as samples. Three to four different sample concentration levels were run four to five times in each assay. The runs were repeated 4 times each to determine inter-assay (between run) precision. The results are summarized in the table below:

Conclusion

Enzymatic NBS methods for total galactose, phenylalanine, G-6-PD and biotinidase including the DBS sample extraction step can be processed with clinically useful accuracy and precision using the Awareness Technology ChemWell-2 automated analyzer.
B-040 Performance Evaluation of Five Reproductive Endocrinology Assays on the Atellica CI 1900 Analyzer
Authors: Zhang H , Frenna J , Halik L , Ozgen N , Quintanilla M , Rhea-McManus J , Leipold H
Published: September 2023

Background

The Atellica® CI 1900 Analyzer is an automated, mid-throughput, integrated chemistry and immunoassay analyzer utilizing both Atellica CH and Atellica IM assays. This study was designed to evaluate the analytical performance of the Atellica IM Luteinizing Hormone (LH), Progesterone (PRGE), Follicle Stimulating Hormone (FSH), Prolactin (PRL), and Total hCG (ThCG) assays* on the Atellica CI 1900 Analyzer.

Methods

The Atellica CI 1900 LH, PRGE, FSH, PRL, and ThCG assays use the same reagents and calibrators as the comparable Atellica IM assays. Precision and method comparison (MC) studies were used as performance indicators for the Atellica CI 1900 Analyzer. Precision studies were performed according to CLSI EP05-A3 using quality control material and native and contrived human serum samples. One aliquot of each sample pool was tested in duplicate in two runs per day ≥2 hours apart on each analyzer for ≥20 days with one reagent lot on two systems. MC studies were performed according to CLSI EP09-A3. Individual native human serum samples were analyzed using the Atellica IM assays on both the Atellica IM and Atellica CI 1900 Analyzers.

Results

Representative precision and MC results are listed for each assay in the table. Over the five assays tested, repeatability and within-lab %CVs were <7% and <13.5%, respectively. Slopes determined by the Deming linear regression model were approximately equal to 1.

Conclusion

Evaluation of the Atellica IM LH, PRGE, FSH, PRL, and ThCG assays using the Atellica CI 1900 Analyzer demonstrated good precision and equivalent performance compared to the same assays on the Atellica IM Analyzer.

*The products/features mentioned here are not commercially available in all countries. Their future availability cannot be guaranteed.
B-041 Evaluation of a Nuclear Magnetic Resonance Spectroscopy-Based Method for Estimating Glomerular Filtration Rate Using Creatinine, Cystatin C, Myo-Inositol, and Valine
Authors: Branson L , Southard D , Hadder B , Katrangi W , Alturkmani R
Published: September 2023

Background

Timely and accurate monitoring of renal dysfunction is critical for patients with chronic kidney disease (CKD). Most equations currently used for estimating glomerular filtration rate (GFR) incorporate serum levels of creatinine and/or cystatin C. Here, we evaluate a recently introduced method for estimating GFR that uses nuclear magnetic resonance spectroscopy (NMR) to measure creatinine, myo-inositol, and valine in combination with cystatin C measured by immunoassay, and patient’s age and sex (eGFRNMR).

Methods

Serum creatinine, valine, and myo-inositol measurements were performed simultaneously by an NMR assay on a Bruker Avance III HD 600 MHz NMR instrument (Bruker Corporation, MA). Cystatin C testing was performed using an immunoturbidimetric assay (Diazyme Laboratories, CA) on a cobas 8000 analyzer (Roche Diagnostics, IN). Within-run and between-day precision studies were performed across 5 days. Method comparison was carried out by testing 86 split serum samples from adult individuals against the numares AG GFR (NMR) assay. Of the 86 samples, 20 were spiked with various concentrations of creatinine, myo-inositol, and valine to reach a wide range of GFR results. An additional method comparison study was performed against Mayo Clinic Laboratories (Rochester, MN) on 59 serum samples from adult patients that had already been tested using the same assay. Measured GFR (mGFR) was also performed on these patients by Mayo Clinic Laboratories using urinary iothalamate clearance.

Results

Within-run and between-day coefficients of variation (%CV) for eGFRNMR did not exceed 6%. The eGFRNMR measurement range was confirmed at 10 to 157 mL/min/1.73 m2 based on verified analytical measurement ranges of creatinine (0.28–9.8 mg/dL), myo-inositol (39–430 µmol/L), and valine (30–1250 µmol/L). Method comparison studies against both numares AG and Mayo Clinic Laboratories demonstrated excellent concordance (r2 = 0.95 and r2 = 0.97, respectively) and minimal bias (4.1% and −0.3%, respectively) with results ranging from 21 to 157 mL/min/1.73 m2. When the 59 patients who had their GFR measured were staged by their mGFR results according to the CKD classification ranges of <15, 15–29, 30–44, 45–59, 60–89, and ≥90 mL/min/1.73 m2, eGFRNMR showed higher classification concordance with mGFR (69%) than the CKD-EPI 2021 creatinine-cystatin C equation (63%).

Conclusion

Our evaluation confirms the excellent analytical and clinical performance of the recently introduced eGFRNMR assay, supporting its integration into clinical practice for improved estimation of GFR.
B-043 Thermal Evaluation and Field Study of Labcorp TrueThermTMpackaging System for Protecting Sub-Milliliter Blood Samples
Authors: Schaff U , Iacovetti G , Collier B , Setzer S , Peevler M , Ragar J , Brandon W , Chappell M , Grant R P , Sommer G J
Published: September 2023

Background

Many diagnostic assays require temperature-controlled sample storage and shipment to ensure accuracy. Here we present, the Labcorp TrueTherm, designed for thermal-controlled shipment of small volume blood samples. The reusable TrueTherm combines a stainless steel vacuum bottle with a custom internal cold pack and insulating stopper. Users refrigerate the cold pack to protect against warm or cold temperature excursions. The whole system is relatively compact, measuring about 10in (25cm) in length, 3 inches (8cm) in diameter, and 2.5 pounds (1kg) in weight.

Methods

In order to evaluate thermal performance, the TrueTherm system was exposed to both ISTA-7D summer and winter conditions and internal temperature was recorded for 96hrs. Subsequently, venous blood samples were collected from n = 40 subjects, and immediately aliquoted into BD SST (Serum separator) Microtainers®. For each subject, sub-samples were subjected to centrifugal separation (provided by the Labcorp TrueSpinTM battery-powered centrifuge), serum removal, and 24hr insulated shipping on ice packs compared to a variety of 72hr cross-country shipping conditions with and without centrifugal separation and with and without insulated packaging (including TrueTherm) during August 2022.

Results

TrueTherm maintained temperature between 2 and 20C for 72hrs under simulated summer and winter conditions. Under actual cross-country summer commercial shipping conditions, both centrifugal separation and thermal control via TrueTherm expanded the number of valid analytes compared to unprotected whole blood (see Table 1).

Conclusion

The results suggest that TrueTherm is an effective system for protecting small blood samples from thermal extremes during extended shipping. Portable thermal moderation was complimentary with portable centrifugal separation to maximize stability of common analytes.
B-058 Development and Evaluation of the Assay for Detection of Human Specific IgE Against Animal Dander Allergens on a Fully Automated Chemiluminescence Immunoassay Platform—Autolumo® A2000 Plus
Authors: Rezaei S , Yang X , Xi I , Zhao D , Han J , Zhu K , Li Z , Lee C
Published: September 2023

Background

The detection of specific IgE is a key method for diagnosing allergic diseases. An accurate, user friendly and cost-effective way to clinically diagnosing allergies is beneficial for the patients. Our detection kit together with the Autolumo A2000 Plus chemiluminescence fully automated platform provide a new and more effective (40 minutes) way for detection of specific IgE with simple operation, high sensitivity and specificity.

Methods

The Animal Dander Allergen Mix Assay kit detects specific IgE against cat dander (E1), horse dander (E3), cow dander (E4) and dog dander (E5). Performance evaluation of the animal dander mix, E1, E3, E4 and E5 assay kits for the detection of specific IgE in serum was performed on our automated chemiluminescence platform (Autolumo A2000 Plus) and compared to a well-characterized platform (ImmunoCAP, Phadia). During detection, magnetic particle suspension, antigen solution, patient sample, and enzyme conjugate were added sequentially. A streptavidin-biotinylated antigen-sIgE antibody-anti-IgE-HRP conjugate complex is formed, wherein the amount of the anti-IgE-HRP conjugate is positively correlated to the amount of sIgE antibodies in the patient sample. After the substrate is added, the HRP catalyze the chemical reaction to generate a recordable signal in the form of light. The intensities of the light were obtained by using a chemiluminescence quantitative analyzer, and the standard curve was generated according to the 7-point calibration, and then the sIgE antibody concentrations in the serum sample were analyzed. The overall agreement, method comparison, precision, linearity, and stability of our mixed and single assay kits were evaluated using serum samples (n > 140) that had been characterized with Phadia.

Results

The overall agreement for the animal dander mix assay is 91.84%, with the average intra-run and inter-run precision to be 1.97% and 4.21% respectively. The limit of blank (LoB) and limit of detection (LoD) for the animal dander mix assay is 0.019 kU/L and 0.045 kU/L respectively. The sensitivity for our single E1, E3, E4, and E5 assays are 97%, 85.6%, 70.8%, and 80.2%, respectively. All single assays have a specificity >90%, total precision <5% CV, and a linearity with R2 > 0.999. The LoB, LoD and recommended LoQ for all single assays are 0.019 kU/L, 0.037 kU/L, and 0.1 kU/L respectively. The average signal drifts after 10 days incubation in 37C is less than 10% indicating the assays are stable.

Conclusion

Autolumo A2000 Plus is a fully automated chemiluminescence Immunoassay platform that provides accurate and cost-effective screening for allergy diagnostics with excellent overall agreement, precision, and stability.