Antibody Test For Diagnosis Research Articles

Infectious Diseases Society of America Guidelines on the Diagnosis of COVID-19: Serologic Testing.

The role of serologic testing for SARS-CoV-2 has evolved during the pandemic as seroprevalence in global populations has increased. The Infectious Diseases Society of America (IDSA) convened an expert panel to perform a systematic review of the coronavirus disease 2019 (COVID-19) serology literature and construct updated best practice guidance related to SARS-CoV-2 serologic testing. This guideline is an update to the fourth in a series of rapid, frequently updated COVID-19 guidelines developed by IDSA. To develop evidence-based recommendations and identify unmet research needs pertaining to the use of anti-SARS-CoV-2 antibody tests for diagnosis, decisions related to vaccination and administration of monoclonal antibodies or convalescent plasma in immunocompromised patients, and identification of a serologic correlate of immunity. A multidisciplinary panel of infectious diseases clinicians, clinical microbiologists and experts in systematic literature reviewed, identified, and prioritized clinical questions related to the use of SARS-CoV-2 serologic tests. Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess the certainty of evidence and make testing recommendations. The panel recommends against serologic testing to diagnose SARS-CoV-2 infection in the first two weeks after symptom onset (strong recommendations, low certainty of evidence). Serologic testing should not be used to provide evidence of COVID-19 in symptomatic patients with a high clinical suspicion and repeatedly negative nucleic acid amplification test results (strong recommendation, very low certainty of evidence). Serologic testing may assist with the diagnosis of multisystem inflammatory syndrome in children (strong recommendation, very low certainty of evidence). To seek evidence for prior SARS-CoV-2 infection, the panel suggests testing for IgG, IgG/IgM, or total antibodies to nucleocapsid protein three to five weeks after symptom onset (conditional recommendation, low certainty of evidence). In individuals with previous SARS-CoV-2 infection or vaccination, we suggest against routine serologic testing given no demonstrated benefit to improving patient outcomes (conditional recommendation, very low certainty of evidence.) The panel acknowledges further that a negative spike antibody test may be a useful metric to identify immunocompromised patients who are candidates for immune therapy. The high seroprevalence of antibodies against SARS-CoV-2 worldwide limits the utility of detecting anti-SARS CoV-2 antibody. The certainty of available evidence supporting the use of serology for diagnosis was graded as very low to low. Future studies should use serologic assays calibrated to a common reference standard.

Availability and access to pediatric diabetes care: a global descriptive study.

A decade since the discovery of insulin, the increasing prevalence of type 1 diabetes mellitus (T1DM) has underscored the prevailing inequalities in the provision of essential care for T1DM worldwide. However, the details on the availability of insulin types and associated medical devices remain unclear. A cross-sectional electronic survey was distributed across a global network of pediatric societies under the umbrella of the International Pediatric Association (IPA). Access to and availability of pediatric diabetes care were investigated using standardized questions. Responses from 25 of 132 pediatric societies across six regions were included. Pediatric endocrinologists typically manage T1DM together with pediatricians or adult endocrinologists. Nonetheless, 24% of the respondents reported pediatricians to be the sole healthcare professionals. According to the respondents, the patients were either partially or completely responsible for payments of insulin (40%), A1C (24%), C-peptide (28%), and antibody testing for diagnosis (28%). Government support is generally available for insulin, but this was merely 20% for insulin pumps and 12% for continuous glucose monitors. There are considerable disparities in the access, availability, and affordability of diabetes testing, medications, and support between countries with significant out-of-pocket payments for care. Country- and region-specific improvements to national programs are necessary to achieve optimal pediatric diabetes care globally.

VP.39 A new era for gMG management: Impact of continuing education on improving diagnosis and classification of gMG patients

The management of gMG is changing with the advent of targeted therapeutics and an expanding pipeline. HCPs need to know how to use biomarkers and antibody testing to better individualize therapeutic decisions. We assessed the impact of online continuing medical education (CME) for clinicians (HCPs) on competence related to generalized myasthenia gravis (gMG) diagnosis and knowledge of current and new and emerging treatment options. One 60-min CME activity was launched live-online on 3/9/21 and remained on-demand for 1 year. Test questions were administered pre-, immediately post-, and 2 months post-activity. Responses from learner polling and follow-up surveys were analyzed for engagement, lessons learned, and continuing gaps. Chi-square compared paired responses (pre/post & pre/2 mos, p<.05). When the activity expired, 906 HCPs engaged with the activity, 223 of them reporting 9.4 patient visits for MG every month. Results showed statistically significant immediate increases in knowledge related to treatment-resistant gMG disease burden (76% post vs 30% pre), therapeutic predictive value of gMG associated antibodies (84% post vs 39% pre), and mechanisms of action of new immunoglobulin G (IgG) and emerging neonatal Fc receptor (FcRn) targeted agents (87% post vs 39% pre). During the follow-up survey, 88% of HCPs reported the education to benefit their clinical practice, with write-in examples of changes related to implementation of EMG and antibody testing for diagnosis, increased awareness of new treatments options, and enhanced ability to provide patient counseling regarding management options. These data support the positive impact of live and on-demand online CME education on awareness of gMG burden, diagnosis, prognosis based on biomarkers, and its evolving management. The education also revealed areas in need for continuous education regarding the impact on gMG burden on treament selection, and strategies to individualize therapy.

Infectious Diseases Society of America Guidelines on the Diagnosis of COVID-19:Serologic Testing.

BackgroundThe availability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic testing has rapidly increased. Current assays use a variety of technologies, measure different classes of immunoglobulin or immunoglobulin combinations and detect antibodies directed against different portions of the virus. The overall accuracy of these tests, however, has not been well-defined. The Infectious Diseases Society of America (IDSA) convened an expert panel to perform a systematic review of the coronavirus disease 2019 (COVID-19) serology literature and construct best practice guidance related to SARS-CoV-2 serologic testing. This guideline is the fourth in a series of rapid, frequently updated COVID-19 guidelines developed by IDSA.ObjectiveIDSA’s goal was to develop evidence-based recommendations that assist clinicians, clinical laboratories, patients and policymakers in decisions related to the optimal use of SARS-CoV-2 serologic tests in a variety of settings. We also highlight important unmet research needs pertaining to the use of anti-SARS-CoV-2 antibody tests for diagnosis, public health surveillance, vaccine development and the selection of convalescent plasma donors.MethodsA multidisciplinary panel of infectious diseases clinicians, clinical microbiologists and experts in systematic literature review identified and prioritized clinical questions related to the use of SARS-CoV-2 serologic tests. Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess the certainty of evidence and make testing recommendations.ResultsThe panel agreed on eight diagnostic recommendations.ConclusionsInformation on the clinical performance and utility of SARS-CoV-2 serologic tests are rapidly emerging. Based on available evidence, detection of anti-SARS-CoV-2 antibodies may be useful for confirming the presence of current or past infection in selected situations. The panel identified three potential indications for serologic testing including: 1) evaluation of patients with a high clinical suspicion for COVID-19 when molecular diagnostic testing is negative and at least two weeks have passed since symptom onset; 2) assessment of multisystem inflammatory syndrome in children; and 3) for conducting serosurveillance studies. The certainty of available evidence supporting the use of serology for either diagnosis or epidemiology was, however, graded as very low to moderate.

Evaluation of a rapid immunochromatographic test kit to the gold standard fluorescent antibody test for diagnosis of rabies in animals in Bhutan

BackgroundRabies kills approximately 59,000 people each year worldwide. Rapid and accurate diagnosis of rabies is important for instituting rapid containment measures and for advising the exposed people for postexposure treatment. The application of a rapid diagnostic tests in the field can greatly enhance disease surveillance and diagnostic activities, especially in resource poor settings. In this study, a total of 179 brain tissue samples collected from different rabies suspect animal species (113 dogs, 50 cattle, 10 cats, 3 goats, 2 horses, and 1 bear) were selected and tested using both rapid immunochromatographic kit and the reference standard fluorescent antibody test (FAT). We evaluated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of a rapid antigen detection test kit produced by BioNote, Inc. (Hwaseong-si, Korea) relative to a FAT for its fit-for-purpose for confirmation of clinical cases of rabies for early response and enhancing rabies surveillance.ResultsAmong 179 samples examined in this study, there was a concordance in results by the rapid test and FAT in 115 positive samples and 54 negative samples. Test results were discordant in 10 samples which were positive by FAT, but negative (false negative) by rapid kit. The rapid test kit showed a sensitivity of 92% (95% CI: 85.9–95.6) and specificity of 100% (95% CI: 93.4–100) using FAT as the reference standard. The positive and negative predictive values were found to be 100% (95% CI:96.7–100) and 84.4% (95% CI: 73.6–91.3), respectively. Overall, there was 94.4% (95% CI: 90–96.9) test agreement between rapid test and FAT (Kappa value = 0.874) with a positive percent agreement and negative percent agreement of 92 and 100%, respectively.ConclusionsOur finding demonstrated that the rapid test kit (BioNote) can be used for rabies surveillance and confirming clinical case of rabies in animals for making rapid decisions particularly controlling rabies outbreaks in resource poor settings.

A structured algorithm for judicious use of antibody test in diagnosis of heparin-induced thrombocytopenia (HIT).

314 Background: HIT diagnosis combines 4T scoring &amp; HIT antibodies (HIT-Ab) testing, with confirmatory serotonin release assay (SRA). Latex immunoturbidometric assay (LIA) shows promise in quick &amp; accurate HIT diagnosis, compared to particle immunofiltration assay (PIFA). We designed a HIT workflow &amp; replaced PIFA with LIA at our hospital, to improve 4T usage rates &amp; HIT diagnosis accuracy in a cost-efficient manner. Methods: In phase I, patients (pts) charts with HIT-Ab (PIFA) ordered between Mar2017-Mar2018 were retrospectively reviewed. Three investigators independently calculated 4T &amp; reviewed PIFA/SRA results, with any alternative anticoagulation (AC) used. In phase II, a new workflow on electronic health record incorporating 4T algorithm with HIT-Ab test order was implemented. Our lab replaced PIFA with LIA. In phase II, charts for pts with LIA results from Jan-Mar 2019 were reviewed. Results: In phase I, 170 pts had PIFA results &amp; 5 such pts (0.02%) had 4T score documented in chart. Per investigators, 113 (66.4%) pts had 4T scores. PIFA showed 60% sensitivity &amp; 50% specificity compared to SRA. 19 pts received AC (4 pts had low 4T with negative PIFA). In phase II, 40 pts with LIA tested, 4T scoring by ordering physicians improved to 100%. Per investigators, 42.5% pts had low 4T scores. Clinicians documented high 4T in 11 pts; investigators confirmed high 4T in 2 pts. AC was used in 5 pts (4 with intermediate-high 4T per investigators) Conclusions: Our study showed that incorporation of 4T scoring in HIT algorithm significantly reduced unnecessary ordering of HIT-Ab, with 100% compliance in 4T reporting. Use of AC was consistent with the level of probability by 4T. Further clinician education can help in reduction of up scoring of 4T noted in our results. [Table: see text]

Efficacy of anti-ribosomal P protein antibody testing for diagnosis of systemic lupus erythematosus

Objective. Anti-ribosomal P protein antibody (anti-P) is detected in a fraction of systemic lupus erythematosus (SLE) patients, especially with lupus psychosis, lupus nephritis, and lupus hepatitis. However, it has been unclear whether anti-P testing is specific for SLE. The current studies were designed to examine the efficacy of serum anti-P testing in diagnosis of SLE.Method. Multicenter retrospective study was performed with 102 SLE patients, 102 patients with non-SLE rheumatic diseases, and 100 normal healthy subjects, who gave informed consents. The diagnosis of SLE was confirmed according to the 1982 ACR revised criteria. Serum IgG anti-P was determined by ELISA using the C-terminal 22 amino-acids of ribosomal P protein conjugated to human serum albumin. The specificity and sensitivity of anti-P were compared with those of anti-DNA, anti-Sm, and anti-cardiolipin (CL) antibodies.Results. Serum anti-P was positive in 38 of 102 SLE patients (37.3%), in 4 of 102 patients with non-SLE rheumatic diseases (3.9%), and in none of 100 normal subjects. Receiver operating characteristic (ROC) curve analysis revealed that anti-P provided higher AUC (area under the curve) than anti-Sm or anti-CL. Consistently, the sensitivity of anti-P (37.3%) was superior to that of anti-Sm (27.5%) and anti-CL (24.5%), but inferior to that of anti-DNA (51.0%), whereas the specificity of anti-P (96.1%) was superior to that of anti-CL (86.3%) and comparable to that of anti-DNA (96.1%) and anti-Sm (96.1%).Conclusion. These results indicate that serum anti-P testing might be an effective measure in diagnosing SLE, providing better diagnostic efficiency than anti-Sm and anti-CL.

Letter: follow‐up practices in coeliac disease – intestinal biopsy after child‐to‐adult transition might be useful; authors' reply

We are grateful to Dr Valitutti and colleagues for their insightful comments arising from our recent publication.1, 2 We are particularly glad that they highlighted the 15% of our patients who were seronegative for tissue transglutaminase (TTG) antibodies. Studies frequently cited as demonstrating the performance of the TTG antibody test are often methodologically poor and open to bias that artificially inflates the sensitivity. This is inevitable, given the existence of asymptomatic coeliac disease and the difficulties inherent in performing duodenal biopsies on unselected individuals. Our seronegativity rate is in keeping with existing systematic reviews, such as that from the National Institute for Health and Clinical Excellence,3 and we hope that our paper encourages critical re-appraisal of the sensitivity of the TTG antibody test in diagnosis – and follow-up – of coeliac disease. Existing reviews – including that cited by our colleagues4 – demonstrate a lower sensitivity for endomysial antibodies (EMA) than TTG. In our unpublished audit of 1364 consecutive samples, no patient tested negative for TTG and positive for EMA. Indeed, the higher specificity of EMA has led to its recommendation for confirming a positive TTG test.3 Whilst our seronegative patients are carefully scrutinised for alternative diagnoses, a further benefit of our re-biopsy strategy is the possibility of cross-referencing not only symptomatic relief following gluten withdrawal in these patients but also histological recovery to help confirm the diagnosis. Where the diagnosis remains questionable, we check HLA and/or carry out a gluten re-challenge. We agree that the Marsh 2 category is difficult5 and we generally apply the Corazza definitions both clinically and in this study. We intend that discharge outcomes in our cohort will be the subject of a separate study. Finally, we agree entirely that adolescents transitioning into adult care may benefit from a re-appraisal including a follow-up biopsy and it is routine to offer this in our practice. The authors' declarations of personal and financial interests are unchanged from those in the original article.2

Poor accuracy of anti-citrulline antibody test in diagnosis of rheumatoid arthritis in Iran

We read with interest the article on the utility of anti-CCP in Iran [1]. Although the authors have mentioned that ‘‘anti-CCP was measured by a second-generation ELISA,’’ the authors fail to provide the kit name or the cutoff value recommended by the kit. The study has defined ‘‘more than 15 U/ml as high titer,’’ which suggests they used the Euroimmun anti-CCP ELISA kit (Euroimmun AG, Luebeck, Germany) [2] which recommends a cutoff of 5 RU/ml. However, they mention the ELiA CCP test in the introduction, which recommends a cutoff of 10 U/ml [3]. It will be interesting to know the accuracy (sensitivity and specificity) when using kit-recommended cutoff apart from ‘‘high titer’’ cutoff used in this study. The authors found a sensitivity of anti-CCP to be 81 %, but found a specificity of only 77 %. This low specificity is of concern, being much lower than previously reported and claimed by manufacturers [2–5]. The authors have included 16 patients of ‘‘seronegative arthritis’’ (not defined in the text) out of 100 controls, making one wonder whether some of these were actually rheumatoid arthritis being picked up by the anti-CCP test. Interestingly, this study found rheumatoid factor to have a higher specificity (85 %) than antiCCP (77 %)! Finally, the authors have found 20 RU may be a more appropriate cutoff in their population. This is similar to other studies finding higher cutoffs than those recommended by manufacturers [6] and highlights the need to define population standards, rather than applying kit standards (based on different populations) indiscriminately.

The sensitivity, specificity and accuracy of anti-citrulline antibody test in diagnosis of rheumatoid arthritis

Citrulline antibody, nowadays, is a new item which has been the center of attention due to its much more specificity to diagnose RA. The aim of the present study was to evaluate the efficacy and accuracy of anti-citrulline antibody test in RA diagnosis among hospitalized patients in Iran. Through a case-control study, we tried to calculate the accuracy of anti-cyclic citrullinated peptide antibody (anti-CCP) test used in the diagnosis of RA enrolling 200 participants divided into two groups of the patients with RA, on the one hand, and other diseases, on the other. Anti-CCP was measured by ELISA technique through which titers more than 15 were defined as high titer. Of all the studied population, 81 (81 %) were in active phase of RA, which had anti-CCP >15 U/ml, while only 25 controls (25 %) experienced these levels. The average anti-CCP was 144 U/ml in cases and 16.05 U/ml in controls with a P value <0.001, which confirmed significant difference between the two. Considering different comments on this matter besides our findings in the present research, we offer a combination of anti-citrulline antibody test rather than anti-CCP and RF to get the best results in RA diagnosis, discrimination and prognosis because of 97 % specificity.

Value of IgA human recombinant tissue transglutaminase antibody test in diagnosis of symptomatic celiac disease in children

Objective: To identify the value of serological examination in diagnosis of celiac disease in children. Patients and methods: A prospective case series study was conducted at private clinics in Mosul city during the period from 30th of October 2007 to 30 th of October 2009. A total of 40 patients (29 males, 11 females) aged more than 6 months on gluten containing diet presented with symptoms suggestive of celiac disease were screened by serological testing using second generation ELISAs IgA human recombinant tissue transglutaminase antibody. Multiple duodenal biopsies were performed for every patient enrolled in this study regardless of the results of serology. Statistical methods were used to indicate sensitivity, specificity, negative and positive predictive values of serological test in comparison to biopsy results. Results: A total of 16 (40%) out of 40 symptomatic patients with mean age of 51 months, demonstrated both positive IgA anti-tissue transglutaminase antibody test and biopsy results for celiac disease, the remaining 24 patients (60%) displayed negative results for both serology and biopsy. IgA anti-tissue transglutaminase antibody test had (100%) specificity, sensitivity, positive predictive value, and negative predictive value in relation to biopsy results. Conclusion: Our results provide additional support to the concept that IgA anti-tissue transglutaminase antibodies can be used as a diagnostic serologic marker for celiac disease.

Quality of Lyme Disease Tests

In this issue ofThe Journal, Schwartz and colleagues 1 report interlaboratory differences in serological test results for Lyme disease. Their findings confirm earlier results 2 and show that the rising number of tests performed in areas endemic for this disease can be very high. Lyme disease continues to receive major attention by the news media. Consequently, with the knowledge that the characteristic skin lesion erythema migrans may not always develop and that there is potential for long-term disorders that may be confused with other maladies, the public and the medical community have relied heavily on serum antibody tests for diagnosis. When patients are in the later stages of Lyme disease, marked by neurological or arthritic disorders, clinicians sometimes are faced with great difficulty in making a diagnosis. Like many other laboratory tests, assays for Lyme disease are less than perfect, and, as expressed by Schwartz et al, 1 some

Comparison of tissue culture and direct fluorescent antibody testing for diagnosis of chlamydia in teenagers

Comparison of tissue culture and direct fluorescent antibody testing for diagnosis of chlamydia in teenagers

Clinical Concepts of Infectious Diseases

This book is not a major contribution for infectious disease physicians, academicians, or internists. It may be of benefit to medical students as a general introduction to infectious diseases, but the subjects are treated too superficially to be helpful with the problem patient. For example, viral hepatitis is discussed in six pages and with no mention of its high incidence in homosexuals or the new hepatitis B vaccine. The chapter on endocarditis has only seven pages, and there is very little on coagulase-negative staphylococcal infections, the use of rifampin and vancomycin hydrochloride for resistant staphylococci, or the teichoic acid antibody test in diagnosis and follow-up. The chapters on the dermatologic and hematologic manifestations of infectious disease should be eliminated in any new edition in place of a more complete treatment of the other subjects. The dermatologic chapter does not contain one picture, which we know are worth 1,000 words apiece.

Indirect Fluorescent Antibody Test in Diagnosis of Trichinellosis in Man

Indirect Fluorescent Antibody Test in Diagnosis of Trichinellosis in Man

Legionnaires' Disease: Indirect Fluorescent Antibody Test in Diagnosis

Excerpt To the editor: During the past 2 years, evidence has been accumulated to suggest that the indirect fluorescent antibody (FA) test for diagnosing Legionnaires' disease lacks specificity (1-4...

The indirect fluorescent antibody test for diagnosis of kala-azar infection in Iraq

(1979). The indirect fluorescent antibody test for diagnosis of kala-azar infection in Iraq. Annals of Tropical Medicine & Parasitology: Vol. 73, No. 1, pp. 31-35.

Fluorescent Antibody Test in Diagnosis of Ulcerative Enteritis

A direct fluorescent antibody (FA) test to demonstrate the presence of Clostridium colinum in cryostat sections of liver and intestine from chickens with ulcerative enteritis ("quail disease") was investigated. Both field cases and experimentally infected birds were studied by FA, bacterial isolation of the clostridium, and histopathology. The FA test proved highly specific for Cl. colinum. It was concluded that the described direct FA procedure offers simplicity and speed over bacterial isolation procedures for etiologic diagnosis of ulcerative enteritis.

Indirect fluorescent antibody test in diagnosis of hepatic amoebiasis.

Indirect fluorescent antibody test in diagnosis of hepatic amoebiasis.