scholarly journals Comparative evaluation of six immunoassays for the detection of antibodies against SARS-CoV-2

2020 ◽  
Author(s):  
Felipe Perez-Garcia ◽  
Ramon Perez-Tanoira ◽  
Maria Esther Iglesias ◽  
Juan Romanyk ◽  
Teresa Arroyo ◽  
...  
Keyword(s):  
Excellent Agreement ◽  
Comparative Evaluation ◽  
Diagnostic Performance ◽  
Lateral Flow ◽  
Serum Samples ◽  
Kappa Score ◽  
One Step ◽  
Performance Results

Objectives: Serologic techniques can serve as a complement to diagnose SARS-CoV-2 infection. The objective of our study was to compare the diagnostic performance of six immunoassays to detect antibodies against SARS-CoV-2: three lateral flow immunoassays (LFAs), one ELISA and two chemiluminescence assays (CLIAs). Methods: We evaluated three LFAs (Alltest, One Step and SeroFlash), one ELISA (Dia.Pro) and two CLIAs (Elecsys and COV2T). To assess the specificity, 60 pre-pandemic sera were used. To evaluate the sensitivity, we used 80 serum samples from patients with positive PCR for SARS-CoV-2. Agreement between techniques was evaluated using the kappa score (k). Results: All immunoassays showed a specificity of 100% except for SeroFlash (96.7%). Overall sensitivity was 61.3%, 73.8%, 67.5%, 85.9%, 88.0% and 92.0% for Alltest, One Step, SeroFlash, Dia.Pro, Elecsys and COV2T, respectively. Sensitivity increased throughout the first two weeks from the onset of symptoms, reaching sensitivities over 85% from 14 days for all LFAs, being One Step the most sensitive (97.6%), followed by SeroFlash (95.1%). Dia.Pro, Elecsys and COV2T showed sensitivities over 97% from 14 days, being 100% for COV2T. One Step showed the best agreement results among LFAs, showing excellent agreement with Dia.Pro (agreement=94.2%, k=0.884), COV2T (99.1%, k=0.981) and Elecsys (97.3%, k=0.943). Dia.Pro, COV2T and Elecsys also showed excellent agreement between them. Conclusions: One Step, Dia.Pro, Elecsys and COV2T obtained the best diagnostic performance results. All these techniques showed a specificity of 100% and sensitivities over 97% from 14 days after the onset of symptoms, as well as excellent levels of agreement.

scholarly journals Rapid Serological Tests for SARS-COV-2: Diagnostic Performance of Four Commercial Assays

2020 ◽  
Author(s):  
Sérgio Monteiro de Almeida ◽  
Regiane Nogueira Spalanzani ◽  
Meri Bordignon Nogueira ◽  
Beatriz Sanada Spiri ◽  
Barbara Maria Cavalli ◽  
...  
Keyword(s):  
Diagnostic Performance ◽  
Rapid Test ◽  
Nucleic Acid Amplification ◽  
Control Group ◽  
Serum Samples ◽  
Serological Tests ◽  
Test Kit ◽  
Healthy Control ◽  
One Step ◽  
Substantial Heterogeneity

Abstract Background. This study aimed to assess the diagnostic performance of lateral flow immunochromatographic assays (LFA) of four different manufacturers to identify SARS-CoV-2 antibodies (IgM, IgG or total), comparing them with the nucleic acid amplification test (NAAT) or clinical defined (definite or probable SARS-CoV-2 infection respectively). Methods. 119 serum samples were randomly selected by convenience and distributed in the groups: (1) Group with SARS-CoV-2 infection [n=82; RT-qPCR positive (definite, n=70), and probable (n=12)]; (2) other diseases [n= 27; other viruses identified (n=8), SARS of other etiologies (n=19)]; (3) healthy control group (n=10). LFA essays of four manufacturers were compared: MedTest Coronavírus (COVID-19) IgG/IgM (MedLevensohn, Brazil); COVID-19 IgG/IgM ECO Test (Ecodiagnóstica, Brazil); Camtech COVID-19 IgM/IgG Rapid Test Kit (Camtech Diagnostics Pte Ltd, Singapore); and one Step COVID-19 Test for total antibodies (Guangzhou Wondfo Biotech Co, China).Results. The four tests studied showed high diagnostic performance characteristics for the diagnoses of definite or probable SARS-CoV-2 infection. The best measures were for the Wondfo test: sensitivity (86.59%; 95%CI, 77.26-93.11%); specificity (100%; 90.51-100%); DOR (257; 60-1008); LR+ (33.43; 4.82-231.85); LR− (0.13; 0.08 - 0.23); accuracy (90.76%; 84.06- 95.29%); Matthews Correlation coefficient (MCC) 0.82. Although considering only the probable SARS-CoV-2 infection (PCR-) cases, all the kits studied showed limited values.Conclusion. Our data demonstrate the excellent performance of LFA for the diagnoses of definite or probable SARS-CoV-2 infection. There was substantial heterogeneity in sensitivities of IgM and IgG antibodies among the manufacturers. LFA tests cannot replace molecular diagnostics, but should be used as additional screening tool.

scholarly journals Rapid Serological Tests for SARS-COV-2: Diagnostic Performance of Four Commercial Assays

2020 ◽  
Author(s):  
Sérgio Monteiro de Almeida ◽  
Regiane Nogueira Spalanzani ◽  
Meri Bordignon Nogueira ◽  
Beatriz Sanada Spiri ◽  
Barbara Maria Cavalli ◽  
...  
Keyword(s):  
Diagnostic Performance ◽  
Rapid Test ◽  
Nucleic Acid Amplification ◽  
Control Group ◽  
Serum Samples ◽  
Serological Tests ◽  
Test Kit ◽  
Healthy Control ◽  
One Step ◽  
Substantial Heterogeneity

Abstract Background. This study aimed to assess the diagnostic performance of lateral flow immunochromatographic assays (LFA) of four different manufacturers to identify SARS-CoV-2 antibodies (IgM, IgG or total), comparing them with the nucleic acid amplification test (NAAT) or clinical defined (definite or probable SARS-CoV-2 infection respectively). Methods. 119 serum samples were randomly selected by convenience and distributed in the groups: (1) Group with SARS-CoV-2 infection [n=82; RT-qPCR positive (definite, n=70), and probable (n=12)]; (2) other diseases [n= 27; other viruses identified (n=8), SARS of other etiologies (n=19)]; (3) healthy control group (n=10). LFA essays of four manufacturers were compared: MedTest Coronavírus (COVID-19) IgG/IgM (MedLevensohn, Brazil); COVID-19 IgG/IgM ECO Test (Ecodiagnóstica, Brazil); Camtech COVID-19 IgM/IgG Rapid Test Kit (Camtech Diagnostics Pte Ltd, Singapore); and one Step COVID-19 Test for total antibodies (Guangzhou Wondfo Biotech Co, China).Results. The four tests studied showed high diagnostic performance characteristics for the diagnoses of definite or probable SARS-CoV-2 infection. The best measures were for the Wondfo test: sensitivity (86.59%; 95%CI, 77.26-93.11%); specificity (100%; 90.51-100%); DOR (257; 60-1008); LR+ (33.43; 4.82-231.85); LR− (0.13; 0.08 - 0.23); accuracy (90.76%; 84.06- 95.29%); Matthews Correlation coefficient (MCC) 0.82. Although considering only the probable SARS-CoV-2 infection (PCR-) cases, all the kits studied showed limited values.Conclusion. Our data demonstrate the excellent performance of LFA for the diagnoses of definite or probable SARS-CoV-2 infection. There was substantial heterogeneity in sensitivities of IgM and IgG antibodies among the manufacturers. LFA tests cannot replace molecular diagnostics, but should be used as additional screening tool.

scholarly journals Rapid Serological Tests for Sars-Cov-2: Diagnostic Performance of Four Commercial Assays

2021 ◽  
Author(s):  
Sérgio Monteiro de Almeida ◽  
Regiane Nogueira Spalanzani ◽  
Meri Bordignon Nogueira ◽  
Beatriz Sanada ◽  
Barbara Maria Cavalli ◽  
...  
Keyword(s):  
Diagnostic Performance ◽  
Rapid Test ◽  
Nucleic Acid Amplification ◽  
Control Group ◽  
Serum Samples ◽  
Serological Tests ◽  
Test Kit ◽  
Healthy Control ◽  
One Step ◽  
Substantial Heterogeneity

To assess the diagnostic performance of lateral flow immunochromatographic assays (LFA) of four different manufacturers to identify SARS-CoV-2 antibodies (IgM, IgG or total), comparing them with the nucleic acid amplification test (NAAT) or clinical defined (definite or probable SARS-CoV-2 infection respectively). Methods. 119 serum samples were randomly selected by convenience and distributed in the groups: (1) Group with SARS-CoV-2 infection [n=82; RT-qPCR positive (definite, n=70), and probable (n=12)]; (2) other diseases [n= 27; other viruses identified (n=8), SARS of other etiologies (n=19)]; (3) healthy control group (n=10). LFA essays of four manufacturers were compared: MedTest Coronavírus (COVID-19) IgG/IgM (MedLevensohn, Brazil); COVID-19 IgG/IgM ECO Test (Ecodiagnóstica, Brazil); Camtech COVID-19 IgM/IgG Rapid Test Kit (Camtech Diagnostics Pte Ltd, Singapore); and one Step COVID-19 Test for total antibodies (Guangzhou Wondfo Biotech Co, China). Results. The four tests studied showed high diagnostic performance characteristics for the diagnoses of definite or probable SARS-CoV-2 infection. The best measures were for the Wondfo test: sensitivity (86.59%; 95%CI, 77.26-93.11%); specificity (100%; 90.51-100%); DOR (257; 60-1008); LR+ (33.43; 4.82-231.85); LR− (0.13; 0.08 - 0.23); accuracy (90.76%; 84.06- 95.29%); Matthews Correlation coefficient (MCC) 0.82. Although considering only the probable SARS-CoV-2 infection (PCR-) cases, all the kits studied showed limited values. Conclusion. Our data demonstrate the excellent performance of LFA for the diagnoses of definite or probable SARS-CoV-2 infection. There was substantial heterogeneity in sensitivities of IgM and IgG antibodies among the manufacturers. LFA tests cannot replace molecular diagnostics, but should be used as additional screening tool.

scholarly journals Evaluation of the Dynamiker Cryptococcal Antigen Lateral Flow Assay for the Diagnosis of HIV-Associated Cryptococcosis

2020 ◽  
Author(s):  
Richard Kwizera ◽  
Denis Omali ◽  
Kiiza Tadeo ◽  
John Kasibante ◽  
Morris K. Rutakingirwa ◽  
...  
Keyword(s):  
Predictive Value ◽  
Diagnostic Performance ◽  
Point Of Care ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Sub Saharan Africa ◽  
Serum Samples ◽  
Cryptococcal Antigen ◽  
Asymptomatic Patients ◽  
Sub Saharan

Background: Cryptococcal meningitis is a leading cause of meningitis in sub-Saharan Africa. Given the need for rapid point of care testing, we evaluated the diagnostic performance of the Dynamiker cryptococcal antigen (CrAg) lateral flow assay (LFA). Methods: We assessed the diagnostic performance of the Dynamiker CrAg-LFA compared to the IMMY CrAg-LFA as the reference standard. We tested 150 serum, 115 plasma, 100 cerebrospinal fluid (CSF) samples from HIV patients with symptomatic meningitis and 113 serum samples from patients with suspected asymptomatic cryptococcal antigenemia. Results: Compared to the IMMY CrAg-LFA, sensitivity of Dynamiker CrAg-LFA was 98% in serum, 100% in plasma, 100% in CSF from symptomatic patients and 96% in serum from asymptomatic patients. Specificity was 66% in serum, 61% in plasma, 91% in CSF from symptomatic patients, and 86% in serum from asymptomatic patients. The positive predictive value was 85% in serum, 82% in plasma, 96% in CSF from symptomatic patients, and 69% in serum from asymptomatic patients. The negative predictive value was 94% in serum, 100% in plasma, 100% in CSF from symptomatic patients, and 99% in serum from asymptomatic patients. The inter-assay reproducibility was 100% across the four sample types with no observed discordant results when Dynamiker CrAg-LFA was tested in duplicate. However, a high number of false positives were observed on serum of symptomatic patients (11%), serum of asymptomatic patients (11%) and plasma of symptomatic patients (14%). Conclusion: The Dynamiker CrAg-LFA had excellent sensitivity but poor specificity, particularly when tested on serum and plasma.

scholarly journals Prospective Evaluation of the Turbidimetric β-D-Glucan Assay and 2 Lateral Flow Assays on Serum in Invasive Aspergillosis

2020 ◽  
Author(s):  
Toine Mercier ◽  
Ellen Guldentops ◽  
Katrien Lagrou ◽  
Johan Maertens
Keyword(s):  
Invasive Aspergillosis ◽  
Predictive Value ◽  
Diagnostic Performance ◽  
Lateral Flow ◽  
Added Value ◽  
Prospective Evaluation ◽  
Serum Samples ◽  
Flow Device ◽  
Lateral Flow Assays ◽  
Risk Patients

Abstract Background Invasive aspergillosis (IA) remains a potentially lethal disease and requires timely diagnosis and initiation of antifungal therapy. Recently, the IMMY lateral flow assay (LFA), the OLM Diagnostics lateral flow device (LFD), and the Wako turbidimetric β-d-glucan assay have been approved for use as a diagnostic aid. However, their performance in diagnosing IA on serum samples from at-risk patients and the added value to the existing detection of serum galactomannan remain to be investigated. Methods We prospectively collected serum samples from 239 hematology patients and evaluated the diagnostic performance of these 3 assays while using the 2019 EORTC/MSG definitions (study number S59863/S61797, NCT03004092). Results We identified 5 cases of proven IA, 36 cases of probable IA, and 188 controls. The LFA had the highest negative predictive value (NPV) and sensitivity (0.90 and 0.49, respectively) while galactomannan detection had the highest positive predictive value and specificity (0.93 and 0.99, respectively). Sensitivity was not significantly different between both tests. When used in combination, the highest NPV was seen in patients with a negative LFA and a negative β-d-glucan test. The sensitivity of the LFD was significantly lower than the LFA. After omitting serum galactomannan from the definitions to control for incorporation bias, the sensitivity of the LFA outperformed galactomannan detection (0.41 vs 0.31, P = .046). Conclusions The LFA is a fast and effective alternative to serum galactomannan detection for the diagnosis of IA and is especially useful for centers with low sample throughputs. The addition of the Wako β-D-glucan assay further improves the diagnostic performance.

scholarly journals Evaluation of Serum Cryptococcal Antigen Testing Using Two Novel Semiquantitative Lateral Flow Assays in Persons with Cryptococcal Antigenemia

2020 ◽  
Vol 58 (4) ◽  
Author(s):  
Caleb Skipper ◽  
Kiiza Tadeo ◽  
Emily Martyn ◽  
Elizabeth Nalintya ◽  
Radha Rajasingham ◽  
...  
Keyword(s):  
False Positive ◽  
Diagnostic Performance ◽  
False Negative ◽  
Lateral Flow ◽  
Reference Standard ◽  
Serum Samples ◽  
Cryptococcal Antigen ◽  
Negative Results ◽  
Lateral Flow Assays ◽  
Positive Results

ABSTRACT Early cryptococcal disease can be detected via circulating antigen in blood before fulminant meningitis develops, when early antifungal therapy improves survival. Two semiquantitative cryptococcal antigen (CrAg) lateral flow assays (LFAs) have been developed, but their diagnostic performance has not been defined. Cryopreserved serum samples from HIV-infected Ugandans obtained as part of a prospective CrAg-screening cohort were tested in duplicate for CrAg by the CrAgSQ (IMMY) and CryptoPS (Biosynex) lateral flow assays. Case-controlled diagnostic performance was measured using the FDA-approved CrAg LFA (IMMY) as a reference standard via McNemar’s test. Of 99 serum samples tested, 57 were CrAg positive (CrAg+) by the CrAg LFA reference standard. By CrAgSQ, 57 were read as positive, with 98% sensitivity (56/57; 95% confidence interval [CI], 0.91 to 0.99) and 98% specificity (41/42; 95% CI, 0.88 to 0.99) (McNemar’s, P = 0.99). The sample with a false-negative result by CrAgSQ (n = 1) had a titer of <1:5, while the sample with a false-positive result (n = 1) yielded a 1+ result. By CryptoPS, 52 samples were read as positive, with 88% sensitivity (50/57; 95% CI, 0.76 to 0.95) and 95% specificity (40/42; 95% CI, 0.84 to 0.99) (McNemar’s, P = 0.18). The CryptoPS false-negative results included samples with titers of <1:5 (n = 1), 1:5 (n = 5), and 1:20 (n = 1), while samples with false-positive results by CryptoPS (n = 2) yielded Positive results. The CryptoPS assay missed 35% (7/20) of samples with CrAg LFA titers of ≤1:20. The new semiquantitative CrAg LFAs allow rapid estimation of titer levels in easy-to-perform platforms. The CrAgSQ demonstrated better qualitative sensitivity and specificity than the CryptoPS compared to the reference standard. The exact grading of the CrAgSQ results has some subjectivity, with interreader variability; however, qualitative reads were generally concordant for both assays.

scholarly journals Development and validation of a one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) for rapid detection of ZIKV in patient samples from Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Severino Jefferson Ribeiro da Silva ◽  
Keith Pardee ◽  
Udeni B. R. Balasuriya ◽  
Lindomar Pena
Keyword(s):  
Reverse Transcription ◽  
Rapid Detection ◽  
Quantitative Polymerase Chain Reaction ◽  
Rna Extraction ◽  
Lamp Assay ◽  
Isothermal Amplification ◽  
Serum Samples ◽  
Low Resource ◽  
Loop Mediated Isothermal Amplification ◽  
One Step

AbstractWe have previously developed and validated a one-step assay based on reverse transcription loop-mediated isothermal amplification (RT-LAMP) for rapid detection of the Zika virus (ZIKV) from mosquito samples. Patient diagnosis of ZIKV is currently carried out in centralized laboratories using the reverse transcription-quantitative polymerase chain reaction (RT-qPCR), which, while the gold standard molecular method, has several drawbacks for use in remote and low-resource settings, such as high cost and the need of specialized equipment. Point-of-care (POC) diagnostic platforms have the potential to overcome these limitations, especially in low-resource countries where ZIKV is endemic. With this in mind, here we optimized and validated our RT-LAMP assay for rapid detection of ZIKV from patient samples. We found that the assay detected ZIKV from diverse sample types (serum, urine, saliva, and semen) in as little as 20 min, without RNA extraction. The RT-LAMP assay was highly specific and up to 100 times more sensitive than RT-qPCR. We then validated the assay using 100 patient serum samples collected from suspected cases of arbovirus infection in the state of Pernambuco, which was at the epicenter of the last Zika epidemic. Analysis of the results, in comparison to RT-qPCR, found that the ZIKV RT-LAMP assay provided sensitivity of 100%, specificity of 93.75%, and an overall accuracy of 95.00%. Taken together, the RT-LAMP assay provides a straightforward and inexpensive alternative for the diagnosis of ZIKV from patients and has the potential to increase diagnostic capacity in ZIKV-affected areas, particularly in low and middle-income countries.

scholarly journals Immunodiagnosis of human neurocysticercosis by using semi-purified scolex antigens from Taenia solium cysticerci

2007 ◽  
Vol 40 (2) ◽  
pp. 163-169 ◽  
Author(s):  
Francesco Iudici Neto ◽  
Geraldo Pianetti-Filho ◽  
Ricardo Nascimento Araújo ◽  
Evaldo Nascimento
Keyword(s):  
Sensitivity And Specificity ◽  
Excellent Agreement ◽  
Taenia Solium ◽  
Polyacrylamide Gel ◽  
Parasitic Diseases ◽  
Serum Samples ◽  
Serological Screening ◽  
Crude Antigen ◽  
Normal Individuals ◽  
Confirmatory Tests

Crude antigen and semi-purified proteins from scolices of Taenia solium cysticerci were evaluated for the immunodiagnosis of human neurocysticercosis neurocysticercosis. Semi-purified proteins obtained by electrophoresis on polyacrylamide gel and by electroelution were tested by means of the immunoenzymatic reaction against sera from normal individuals and from patients with neurocysticercosis or other parasitic diseases. The 100kDa protein provided 100% sensitivity and specificity in the immunodiagnosis. When 95 or 26kDa proteins were used, 95 and 100% sensitivity and specificity were obtained, respectively. The assays involving crude antigen and sera from normal individuals or from patients with neurocysticercosis, diluted to 1:256, gave excellent agreement with those in which 100, 95 or 26kDa proteins were tested against the same serum samples diluted to 1:64. (Kappa: 0.95 to 1.00). Crude scolex antigen may be useful for serological screening, while 100, 95 or 26kDa protein can be used in confirmatory tests on neurocysticercosis-positive cases.

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