Seroprevalence of SARS-CoV-2 IgG antibody among healthy blood donors: a single centre study

BackgroundSevere acute respiratory syndrome corona virus 2(SARS-CoV-2), the causative agent of corona virus disease-2019(COVID- 19) which has led to a global pandemic. The true extent of the burden of COVID-19 may be underestimated, and there is need to know the current prevalence of SARS-CoV-2 antibody in population.MethodsThe present study was a cross-sectional study to assess prevalence of SARS-CoV-2 IgG antibody among 586 healthy voluntary blood donors who donated whole blood between mid-December 2020 to January 2021. A chemiluminescence assay was used to detect the presence of SARS-CoV-2 IgG antibody in serum samples in addition to recommended transfusion transmitted infections tests and Signal to Cut Off (S/C) > 1 was considered as reactive for antibody as per manufacturer’s instructions.ResultsIn the present study, 586 healthy voluntary blood donors were enrolled and were screened for SARS- CoV-2 IgG antibody. Out of 586 donors, 52 donors had indeterminate values of SARS-CoV-2 IgG antibody. A total of 534 healthy voluntary blood donors’ samples were included in the present study for analysis. Out of total 534 healthy blood donors, 42.88% (229) were found to be seropositive while 57.11% (305) were found to be seronegative.ConclusionA 43% positivity of SARS-CoV-2 IgG antibody among healthy blood donors was detected which is an indication of presence of infection at community level and majority of the population already has been exposed to SARS-CoV-2 infection. However, there was no statistically significant association of type of blood group and age with seropositivity.     

Seroprevalence of SARS-Coronavirus 2 among asymptomatic healthy blood donors from healthcare and non-healthcare settings: Implications for safety of blood donors and blood collection staff during blood donation

IntroductionSARS-Coronavirus-2 pandemic has adversely affected blood supply as potential blood donors were afraid of acquiring infection in hospital settings. We aimed to compare COVID-19 seroprevalence among asymptomatic blood donors from healthcare and non-healthcare setting to analyse the difference in exposure level of each group as well as the risk of acquiring infection during the process of blood donation.Material and MethodsAnalysis of whole blood donors tested for SARS-CoV-2 IgG antibodies was carried out after categorizing them into healthcare workers (HCW) and non-healthcare workers (NHCW). NHCW were further categorized into residents of containment and non-containment zones and seroprevalence analyzed. Seroprevalence among different ABO blood groups was also analyzed.Results1191 blood donors were tested for SARS-CoV-2 antibodies with 9.5 % seropositivity. Significantly lower seropositivity of 3.2 % (p < 0.001) was observed among HCW as compared to 10.9 % seropositivity in NHCW. Among NHCW no difference in seropositivity was observed based on residence in containment or non-containment zone. Significantly higher (p = 0.012) seroprevalence was observed among A blood group donors (12.5 %) as compared to O blood group donors (6.8 %).ConclusionResults suggests that a blood donor, in a hospital setting is less likely to be exposed to COVID-19 disease than when participating in activities of daily living. It is postulated that the lower seroprevalence among HCW as compared to NHCW reflects differences in knowledge and practice of preventive measures among these groups. The findings should instil confidence among blood donors and motivate them to donate blood without fear.     

SARS-Coronavirus-2 seroprevalence in asymptomatic healthy blood donors: Indicator of community spread

BackgroundThe Corona virus disease 2019 (COVID-19) pandemic caused by SARS -Corona virus-2 (SARS-CoV-2) has been a major concern the world over. Serological surveillance is an important tool to assess the spread of infection in the community. This study attempted to assess the prevalence of antibodies to SARS-CoV-2 among blood donors in Delhi, India during the pre-vaccination period.MethodsSeroprevalence of SARS-CoV2-2 IgG antibodies were determined in blood donors reporting to the Department of Transfusion medicine at a tertiary care hepatobiliary center, in India from September to October 2020. The SARS-CoV-2 IgG antibodies against spike subunit 1 protein were measured using the enhanced chemiluminescence method.ResultsA total of 1066 blood donors were screened. The overall seropositivity for SARS-CoV-2 IgG antibodies was 27.57 % (294/1066). The highest seropositivity was seen in the age group 26?35 years, 46.6 % (137/492), followed by 18?25 years, 28.2 % (83/260), 36?45 years, 19.4 % (57/244), and more than 45 years, 5.8 % (17/70). The seropositivity in the donors who had donated blood previously was 26.1 % (189/723). There was no statistically significant difference amongst seroprevalence in the blood groups, AB blood group (32.6 %, 95 % CI 23.02?43.3), group B (27.2 %, 95 % CI 22.8?32.09 %), group A (27.1 %, 95 % CI 21.8?32.9 %), and group O (27.02 %, 95 % CI 22.3?32.1 %) (p 0.539).ConclusionsThere was significantly higher seropositivity for SARS-CoV-2 antibodies in the voluntary healthy blood donors indicating community spread and large number of asymptomatic cases in Delhi. Higher seroprevalence in younger adults indicated increased exposure to the virus and lack of COVID appropriate behaviour.     

The association of ABO blood group with the asymptomatic COVID-19 cases in India

The COVID-19 pandemic resulted in multiple waves of infection worldwide. The large variations in case fatality rate among different geographical regions suggest that the human susceptibility against this virus varies substantially. Several studies from different parts of the world showed a significant association of ABO blood group and COVID-19 susceptibility. It was demonstrated that individuals with blood group O are at the lower risk of coronavirus infection. To establish the association of ABO blood group in SARS-CoV-2 susceptibility, we for the first time analysed SARS-CoV-2 neutralising antibodies among 509 individuals, collected from three major districts of Eastern Uttar Pradesh region of India. Interestingly, we found neutralising antibodies in a significantly higher percentage of people with blood group AB (0.36) followed by B (0.31), A (0.22) and lowest in people with blood group O (0.11). We further estimated that people with blood group AB are at comparatively higher risk of infection than other blood groups. Thus, among the asymptomatic SARS-CoV-2 recovered people blood group AB has highest, whilst individuals with blood group O has lowest risk of infection.     

Detectable SARS-CoV-2 RNAemia in Critically Ill Patients,but Not in Mild and Asymptomatic Infections

BackgroundThe SARS-CoV-2 pandemic has challenged many of our current routine practices in the treatment and care of patients. Given the critical importance of blood donation and transfusion we analyzed 92 blood samples of individuals infected with SARS-CoV-2 stratified by symptoms.Study Design and MethodsWe therefore tested blood samples for SARS-CoV-2 via RT-PCR targeting the E gene. In addition, we tested each blood sample for anti-SARS-CoV-2 IgG antibodies via ELISA and performed plaque reduction neutralization tests.ResultsSARS-CoV-2 RNA was absent in the blood of mild to asymptomatic patients (57 individuals) and only detectable in individuals with severe COVID-19 who were admitted to the intensive care unit (35 individuals) (n = 6/92 [6.5%]; p = 0.023 Fisher''s exact test). Interestingly, anti-spike IgG antibodies were not significantly higher in intensive care unit patients compared to mild patients, but we found that their neutralizing capacity was disproportionately increased (p < 0.001).ConclusionOur observations support the hypothesis that there are no potential hazards from blood or plasma transfusion of SARS-CoV-2-positive individuals with mild flu-like symptoms and more importantly of asymptomatic individuals.     

Associations between seroprevalence of Helicobacter pylori and ABO/rhesus blood group antigens in healthy blood donors in southwest Iran

ObjectiveTo investigate correlations between ABO/rhesus (Rh) blood group antigens and anti-Helicobacter pylori and anti-cytotoxin-associated gene A (CagA) seropositivity in blood donors.MethodsA total of 311 blood donors were enrolled. ABO and Rh blood groups were determined using hemagglutination tests. Specific anti-H. pylori IgG and anti-CagA IgG antibodies in sera were quantitated by enzyme-linked immunosorbent assay. Correlations between blood groups and anti-H. pylori and anti-CagA seropositivity were evaluated using the Chi-square test.ResultsO+ was the most frequent blood type (38%, n = 118). Anti-H. pylori IgG seropositivity was observed in 240 (77.2%) blood donors, while anti-CagA IgG seropositivity was observed in 132 (42.5%) blood donors. Although seropositivity rates for both anti-H. pylori and anti-CagA IgG were higher in individuals with blood type O, no statistically significant associations were observed between seropositivity and any ABO/Rh blood groups.ConclusionIndividuals with blood type O may have higher rates of H. pylori seropositivity.     

Association between ABO blood group and risk of Crohn’s disease: A case‐control study in the Chinese Han population

BackgroundBlood group O has been reported to be a potentially protective factor for Crohn''s disease (CD) susceptibility in Caucasian and Korean populations, but a similar conclusion was not found in a Chinese study. The present study investigated the potential association in the Chinese Han population.MethodsWe included 275 CD patients, 132 ulcerative colitis (UC) patients and 1201 healthy individuals in this case‐control study. The demographic characteristics and ABO blood group were compared among the three groups. The clinical characteristics and treatment of CD were further investigated according to the blood group distribution.ResultsThe blood group distribution in CD patients was significantly different from healthy controls, and the frequency of O blood in CD patients was significantly lower compared to healthy controls. After adjusting for age and gender, the non‐O blood groups remained significantly associated with CD susceptibility in propensity score‐adjusted and propensity score‐matched analyses. Compared to CD patients with non‐O blood groups, patients with O blood were at a lower risk of developing penetrating disease, more likely to receive immunosuppressant treatment and less likely to receive biological treatment.ConclusionOur results confirmed that non‐O blood groups were significantly associated with an increased risk of CD in the Chinese Han population.     

Association of blood group with COVID-19 disease susceptibility and severity in Saudi Arabia

Background

Novel SARS-CoV-2 (COVID-19) virus has rapidly spread worldwide and was declared a pandemic, making identifying and prioritizing individuals most at risk a critical challenge. The literature describes an association between blood groups and the susceptibility to various viral infections and their severity. Knowing if a specific blood group has more susceptibility to COVID-19 may help improve understanding the pathogenesis and severity of the disease. We aimed to assess the association between ABO/RhD and COVID-19 susceptibility and severity, and to compare results with similar studies in Saudi Arabia.

Study Design and Methods

This study was conducted between March and October 2021 on 600 patients confirmed positive for COVID-19 infection. Patients' data were collected and analyzed. As a control, 8423 healthy blood donors were enrolled as a sample representative of the population for blood group distribution.

Results

More individuals had blood group B in the COVID-19 group in comparison with the control group (24.2% vs. 18%), The opposite was observed among individuals of group O (39.5% vs. 47.3%). The B blood group was predictive of higher risk of mortality. No significant difference in the distribution of RhD was observed between the COVID-19 and the control groups. Neither ABO nor RhD was significantly associated with the severity of COVID-19.

Discussion

Although there was no significant association with the disease severity, the B blood group may be associated with a higher risk for COVID-19 infection. Further studies with a larger sample size are necessary to evaluate this correlation.     

The relationship between immunogenic red blood cell antigens and Human Immunodeficiency Virus infection

Introduction

Evidence suggests that red cell antigens may act as receptors for viruses and bacteria and therefore could be associated with HIV infection. Previous studies have been controversial and therefore the aim of this exploratory study was to analyse the expression of immunogenic red cell antigens in HIV-seropositive individuals and to compare the results to negative donors from South Africa.

Severe Acute Respiratory Syndrome Coronavirus 2 and Blood Safety: An Updated Review

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel human coronavirus first identified in late 2019 and subsequently declared a worldwide pandemic in March 2020. In this review, we provide an overview of the implications of SARS-CoV-2 for blood safety and sufficiency.SummaryApproximately one-third of SARS-CoV-2 infections are asymptomatic. The reported mean incubation period typically varies from 2 to 11 days, but longer periods up to 22 days have been reported. The blood phase of SARS-CoV-2 appears to be brief and low level, with RNAaemia detectable in only a small proportion of patients, typically associated with more severe disease and not demonstrated to be infectious virus. A small number of presymptomatic and asymptomatic blood phase cases have been reported. Transfusion-transmission (TT) of SARS-CoV-2 has not been reported. Therefore, the TT risk associated with SARS-CoV-2 is currently theoretical. To mitigate any potential TT risk, but more importantly to prevent respiratory transmission in donor centers, blood services can implement donor deferral policies based on travel, disease status, or potential risk of exposure and encourage staff vaccination.Key MessagesThe TT risk of SARS-CoV-2 appears to be low. The biggest risk to blood services in the current COVID-19 pandemic is to maintain the sufficiency of the blood supply while minimizing respiratory transmission of SARS-CoV-2 to donors and staff while donating blood.     

Screening for antibodies to HLA class I in apheresis donors following Covid‐19 or SARS-CoV-2 vaccination

Transfusion of HLA-specific antibodies may play a role in induction of TRALI, the transfusion complication responsible for most transfusion-related deaths. In Oslo, we screen our apheresis donors and defer HLA-immunized donors from donation of plasma-rich blood components. During the second year of the Covid-19 pandemic and following the first months of SARS-CoV-2 vaccination, both the virus itself and the vaccines were suspected of inducing de novo production of antibodies to HLA class I in patients. For the blood center, the possibility of finding HLA-antibodies in an increased number of blood donors has serious implications. We therefore conducted a study to map the extent of de novo HLA-specific antibodies in representative donor groups. 106 apheresis donors were screened for antibodies to HLA class I/II following Covid-19 or vaccination with either mRNA or adenovirus-vector vaccines, and the findings were compared to pre-Covid blood samples from the same donors. In addition, we analyzed pre-Covid samples from 11 HLA-antibody-positive donors of Covid convalescence plasma. Only three established thrombapheresis donors were deferred due to vaccine-induced HLA-antibodies. In short, our findings did not support the hypothesis that SARS-CoV-2 virus or vaccination cause de novo HLA immunization in healthy blood donors. However, some donors with pre-existing antibodies showed increased antibody expression, confirming a general boost of the immune response following infection or vaccination.     

A large cohort study of the effects of Lewis,ABO, 13 other blood groups,and secretor status on COVID-19 susceptibility,severity, and long COVID-19

Background

Previous studies have reported Blood type O to confer a lower risk of SARS-CoV-2 infection, while secretor status and other blood groups have been suspected to have a similar effect as well.

Study design and methods

To determine whether any other blood groups influence testing positive for SARS-CoV-2, COVID-19 severity, or prolonged COVID-19, we used a large cohort of 650,156 Danish blood donors with varying available data for secretor status and blood groups ABO, Rh, Colton, Duffy, Diego, Dombrock, Kell, Kidd, Knops, Lewis, Lutheran, MNS, P1PK, Vel, and Yt. Of these, 36,068 tested positive for SARS-CoV-2 whereas 614,088 tested negative between 2020-02-17 and 2021-08-04. Associations between infection and blood groups were assessed using logistic regression models with sex and age as covariates.

Results

The Lewis blood group antigen Le^a displayed strongly reduced SARS-CoV-2 susceptibility OR 0.85 CI[0.79–0.93] p < .001. Compared to blood type O, the blood types B, A, and AB were found more susceptible toward infection with ORs 1.1 CI[1.06–1.14] p < .001, 1.17 CI[1.14–1.2] p < .001, and 1.2 CI[1.14–1.26] p < .001, respectively. No susceptibility associations were found for the other 13 blood groups investigated. There was no association between any blood groups and COVID-19 hospitalization or long COVID-19. No secretor status associations were found.

Discussion

This study uncovers a new association to reduced SARS-CoV-2 susceptibility for Lewis type Le^a and confirms the previous link to blood group O. The new association to Le^a could be explained by a link between mucosal microbiome and SARS-CoV-2.     

Characteristics of US Blood Donors Testing Reactive for Antibodies to SARS-CoV-2 Prior to the Availability of Authorized Vaccines

In the United States, many blood collection organizations initiated programs to test all blood donors for antibodies to SARS-CoV-2, as a measure to increase donations and to assist in the identification of potential donors of COVID-19 convalescent plasma (CCP). As a result, it was possible to investigate the characteristics of healthy blood donors who had previously been infected with SARS-CoV-2. We report the findings from all blood donations collected by the American Red Cross, representing 40% of the national blood supply covering 44 States, in order to characterize the seroepidemiology of SARS-CoV-2 infection among blood donors in the United States, prior to authorized vaccine availability. We performed an observational cohort study from June 15th to November 30th, 2020 on a population of 1.531 million blood donors tested for antibodies to the S1 spike antigen of SARS-CoV-2 by person, place, time, ABO group and dynamics of test reactivity, with additional information from a survey of a subset of those with reactive test results. The overall seroreactivity was 4.22% increasing from 1.18 to 9.67% (June 2020 - November 2020); estimated incidence was 11.6 per hundred person-years, 1.86-times higher than that based upon reported cases in the general population over the same period. In multivariable analyses, seroreactivity was highest in the Midwest (5.21%), followed by the South (4.43%), West (3.43%) and Northeast (2.90%). Seroreactivity was highest among donors aged 18-24 (Odds Ratio 3.02 [95% Confidence Interval 2.80-3.26] vs age >55), African-Americans and Hispanics (1.50 [1.24-1.80] and 2.12 [1.89-2.36], respectively, vs Caucasian). Group O frequency was 51.5% among nonreactive, but 46.1% among seroreactive donors (P< .0001). Of surveyed donors, 45% reported no COVID-19-related symptoms, but 73% among those unaware of testing. Signal levels of antibody tests were stable over 120 days or more and there was little evidence of reinfection. Evaluation of a large population of healthy, voluntary blood donors provided evidence of widespread and increasing SARS-CoV-2 seroprevalence and demonstrated that at least 45% of those previously infected were asymptomatic. Epidemiologic findings were similar to those among clinically reported cases.     

Molecular genotyping of Indian blood group antigens amongst regular voluntary blood donors of Surat city,Gujarat, India

BackgroundThere is paucity of data related to the prevalence of the rare blood group antigens amongst South Gujarat blood donor population due to unavailability and high cost of antisera. Therefore it is difficult to screen donors for such rare antigens by gold standard haemagglutination assay. The single nucleotide polymorphism (SNPs) of In^a and In^b antigens is the base of the PCR based detection methods that help to detect these alleles in regular voluntary blood donors.Materials & methodsBlood samples of 200 unrelated regular voluntary blood donors wee collected. DNA was extracted using phenol-chloroform method and genotyped for Indian (In^a/IN*01, In^b/IN*02) blood group alleles by Sequence Specific PCR. In^a antigen positivity was confirmed by serology test.ResultsFour donors were found heterozygous for In^a antigen i.e. In (a + b+) by SS-PCR and their In^a positivity were confirmed by in-house polyclonal Anti-In^a reagent. SS-PCR was standardized using known heterozygous sample of a blood donor. The frequency of In^a antigen (2.0 %) was higher than Caucasians, lower than Iranians and Arabs while comparable to those reported among Indians of Mumbai city.ConclusionIn absence or unavailability of antisera particularly for low frequency alleles like In^a, such PCR based method would be extremely helpful to prepare rare donor registry by screening blood donors’ at large scale. Red cells of In^a positive donors can be used as in-house reagent red cells for screening and identification of corresponding antibody.     

ABO antibody titer performance characteristics and correlates between two automated platforms

BackgroundAABB standards require a policy for assessing transfusing ABO-incompatible plasma. After a fatal hemolytic event with incompatible plasma, our institution instituted platelet donor population titer method for ABO antibodies on the PK7300, with high-titer being defined as having isohemagglutinin titers greater than 256. We recently switched titering platforms to the Neo Iris and we seek to determine the equivalent isohemagglutinin high-titer cutoff on the Neo Iris as compared to the PK7300.MethodsWe measured the titers on 299 apheresis platelet donors and compared its performance characteristics at various cutoffs to the PK7300 reference standard. Discrepant results were manually diluted and retested on the Neo Galileo. Furthermore, since the Neo Iris is able to determine isotype and antigen specific titers, we also characterized these features in our donor population.ResultsIgM titer of 128 on the Neo Iris has better accuracy compared to the titer of 64 (94 % vs 93.6 %). Eleven of sixteen discordant results were in agreement with Neo Iris. Blood group O had the highest IgG antibody titers for both anti-A and anti-B (p = 8.4E-17 and 4.3E-09, respectively). Additionally, group O donors exhibited lower anti-A2 than anti-A1 IgG titers.DiscussionThe Neo Iris titer cut-off of 128 had the best overall accuracy and correlation with a 256 cut-off on our laboratory developed test on the PK7300 platform. Additionally, we found that group O donors had the highest titer antibodies, with typically higher IgG titers than IgM, and generally multiple dilution levels greater than other blood types.     

SARS-CoV-2 B cell receptor signatures in at-risk populations

Many individuals possess B cells capable of recognizing epitopes on the spike glycoprotein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this issue of the JCI, Paschold and Simnica et al. interrogated the frequency of SARS-CoV-2–specific B cell receptor rearrangements in healthy subjects based on age and cancer status. The authors found that while SARS-CoV-2–specific antibody signatures can be identified in the repertoires of young, healthy individuals, such sequences are less frequent in elderly subjects or patients with cancer. Overall, this study sheds light on B cell repertoire restrictions that might lead to an unfavorable clinical course of coronavirus disease 2019 infection in at-risk populations.     

Seroprevalence of SARS-CoV-2 antibodies among healthy blood donors in Karachi,Pakistan

BackgroundCovid-19 spread through blood transfusion has not yet been reported. Despite the prevailing pandemic, there are no recommendations available as yet for testing SARS-CoV-2 antibodies as part of blood screening.ObjectiveTo determine the seroprevalence of SAR-CoV-2 antibodies, its clinical significance and to identify if total antibodies(IgA, IgM, IgG) should be tested or just the specific IgG antibodies only.MethodConsecutive blood donors donated were screened for standard serological panel of HbsAg, Anti-HCV, Anti-HIV and Syphilis using Cobas-411 analyser and Malaria. All seronegative donors were then screened for COVID serology using the same instrument. These results were compared with the blood donors’ seroprevalence checked in a cohort in the first week of June 2020. Pre-COVID-19 period (October 2019) blood donors’ archived samples were also compared. Donors who were positive on ECLIA were then tested for specific antibodies (IgM or IgG) by ELISA.ResultsA total of 380 healthy blood donors were included. All were males with the mean age being 30.6 ± 6.3 years. Ten pre-pandemic samples did not show COVID-19 antibodies, whereas out of 70 samples in the 3rd week of June, only 15 (21.4 %) were positive. However, in July out of the 300 blood donors, 113 (37.7 %) were found to be reactive. To reconfirm our findings, these 113 donors were then tested on ELISA for presence of IgG specifically. Out of these 128 samples, 81 were IgG positive, 23 were borderline positive and 24 were negative.ConclusionAlmost 40 % of blood donors are now seroconverted for COVID-19. This is a reflection of widespread seroprevalence in the adult male population.     

High-Resolution Melting Curve Analysis to Predict Extended Blood Group Phenotypes among Thai Donors and Patients

BackgroundHigh-resolution melting (HRM) analysis is an alternative method for red cell genotyping. Differences in melting curves between homozygous and heterozygous genotypes can predict phenotypes in blood group systems based on single-nucleotide polymorphisms. This study aimed to implement HRM analysis to predict additional extended blood group phenotypes in Thai donor and patient populations.MethodsBlood samples obtained from 300 unrelated Thai blood donors and 23 patients with chronic transfusions were included. HRM analysis was developed and validated in genotyping of KEL*01 and KEL*02, JK*01 and JK*02, FY*01, FY*02, and FY*02 N.01, DI*01 and DI*02, GYPB*03 and GYPB*04, RHCE*E and RHCE*e, and DO*01 and DO*02. Then genotyping results from HRM and polymerase chain reaction with sequence-specific primer (PCR-SSP) and phenotyping results were compared.ResultsThe validated genotyping results in known DNA controls by HRM analysis agreed with DNA sequencing. The genotyping results among 300 donors in 15 alleles by HRM analysis were in complete concordance with those obtained by serological testing and PCR-SSP. The sensitivity and specificity of the HRM assay were both 100%. Among patients, 13 had alloantibodies that possessed predicted antigen-negative phenotypes corresponding to those antibody specificities, and the highest probability of genotyped-matched donors was given to the remaining patients.ConclusionsWe developed and implemented the HRM analysis assay for red cell genotyping to predict extended blood group antigens in Thai donor and patient populations. The data from this study may help inform about and support transfusion care of Thai patients to reduce the risk of alloimmunisation.     

A systematic review and meta-analysis of the prevalence of Leishmania infection in blood donors

Background

The risk of transfusion transmitted leishmaniasis (TTL) from apparently healthy persons or asymptomatic individuals, should not be ignored. Lack of a comprehensive review, encouraged us to design a systematic review with meta-analysis approach to assess the prevalence of Leishmania infection in healthy blood donors.

Rapid Serological Tests for SARS-CoV-2: Diagnostic Performance of 4 Commercial Assays

ObjectiveTo assess the diagnostic performance of lateral flow immunochromatographic assays (LFAs) of 4 different manufacturers to identify SARS-CoV-2 antibodies (IgM, IgG, or total), comparing them with the nucleic acid amplification test (NAAT) or the clinical defined test (definite or probable SARS-CoV-2 infection, respectively).MethodsOne hundred nineteen serum samples were randomly selected by convenience and distributed in the following 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] and SARS of other etiologies [n = 19]); and (3) healthy control group (n = 10). LFAs of 4 manufacturers were compared: MedTest Coronavirus (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 1-Step COVID-19 Test for total antibodies (Guangzhou Wondfo Biotech Co., China).ResultsThe 4 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; 60–1,008), LR+ (33.43; 4.82–231.85), LR− (0.13; 0.08–0.23), accuracy (90.76%; 84.06–95.29%), and Matthews correlation coefficient (MCC) 0.82. Although considering only the probable SARS-CoV-2 infection (PCR−) cases, all the kits studied showed limited values.ConclusionOur 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 different kits. LFA tests cannot replace molecular diagnostics but should be used as an additional screening tool.