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BMC Infectious Diseases Nov 2023Parasitological investigation of bone marrow, splenic or lymph node aspirations is the gold standard for the diagnosis of visceral leishmaniasis (VL). However, this... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Parasitological investigation of bone marrow, splenic or lymph node aspirations is the gold standard for the diagnosis of visceral leishmaniasis (VL). However, this invasive test requires skilled clinical and laboratory staff and adequate facilities, and sensitivity varies depending on the tissue used. The direct agglutination test (DAT) is a serological test that does not need specialised staff, with just minimal training required. While previous meta-analysis has shown DAT to have high sensitivity and specificity when using parasitology as the reference test for diagnosis, meta-analysis of DAT compared to other diagnostic techniques, such as PCR and ELISA, that are increasingly used in clinical and research settings, has not been done.
METHODS
We conducted a systematic review to determine the diagnostic performance of DAT compared to all available tests for the laboratory diagnosis of human VL. We searched electronic databases including Medline, Embase, Global Health, Scopus, WoS Science Citation Index, Wiley Cochrane Central Register of Controlled Trials, Africa-Wide Information, LILACS and WHO Global Index. Three independent reviewers screened reports and extracted data from eligible studies. A meta-analysis estimated the diagnostic sensitivity and specificity of DAT.
RESULTS
Of 987 titles screened, 358 were selected for full data extraction and 78 were included in the analysis, reporting on 32,822 participants from 19 countries. Studies included were conducted between 1987-2020. Meta-analysis of studies using serum and DAT compared to any other test showed pooled sensitivity of 95% (95%CrI 90-98%) and pooled specificity of 95% (95%CrI 88-98%). Results were similar for freeze-dried DAT and liquid DAT when analysed separately. Sensitivity was lower for HIV-positive patients (90%, CrI 59-98%) and specificity was lower for symptomatic patients (70%, CrI 43-89%). When comparing different geographical regions, the lowest median sensitivity (89%, CrI 67-97%) was in Western Asia (five studies).
CONCLUSIONS
This systematic review and meta-analysis demonstrates high estimated pooled sensitivity and specificity of DAT for diagnosis of VL, although sensitivity and specificity were lower for different patient groups and geographical locations. This review highlights the lack of standardisation of DAT methods and preparations, and the lack of data from some important geographical locations. Future well-reported studies could provide better evidence to inform test implementation for different patient populations and use cases.
PROSPERO REGISTRATION
CRD42021240830.
Topics: Humans; Leishmaniasis, Visceral; Agglutination Tests; Serologic Tests; Sensitivity and Specificity; HIV Seropositivity
PubMed: 37946107
DOI: 10.1186/s12879-023-08772-1 -
Frontiers in Cellular and Infection... 2020Toxoplasmosis is a widely distributed zoonotic infection caused by the obligate intracellular apicomplexan parasite . It is mainly transmitted through the ingestion of... (Review)
Review
Toxoplasmosis is a widely distributed zoonotic infection caused by the obligate intracellular apicomplexan parasite . It is mainly transmitted through the ingestion of oocysts shed by an infected cat acting as its definitive host. The key to effective control and treatment of toxoplasmosis is prompt and accurate detection of infection. Several laboratory diagnostic methods have been established, including the most commonly used serological assays such as the dye test (DT), direct or modified agglutination test (DAT/MAT), indirect hemagglutination test (IHA), latex agglutination test (LAT), indirect immunofluorescent test (IFAT), enzyme-linked immunosorbent assays (ELISA), immunochromatographic tests (ICT), and the western blot. Nonetheless, creating specific and reliable approaches for serodiagnosis of infection, and differentiating between acute and chronic phases of infection remains a challenge. This review provides information on the current trends in the serodiagnosis of human toxoplasmosis. It highlights the advantages of the use of recombinant proteins for serological testing and provides insight into the possible future direction of these methods.
Topics: Agglutination Tests; Animals; Antibodies, Protozoan; Cats; Enzyme-Linked Immunosorbent Assay; Humans; Serologic Tests; Toxoplasma; Toxoplasmosis, Animal
PubMed: 32457848
DOI: 10.3389/fcimb.2020.00204 -
BMC Infectious Diseases Feb 2024Leptospirosis is an underdiagnosed infectious disease with non-specific clinical presentation that requires laboratory confirmation for diagnosis. The serologic... (Meta-Analysis)
Meta-Analysis
Diagnosis of human leptospirosis: systematic review and meta-analysis of the diagnostic accuracy of the Leptospira microscopic agglutination test, PCR targeting Lfb1, and IgM ELISA to Leptospira fainei serovar Hurstbridge.
BACKGROUND
Leptospirosis is an underdiagnosed infectious disease with non-specific clinical presentation that requires laboratory confirmation for diagnosis. The serologic reference standard remains the microscopic agglutination test (MAT) on paired serum samples. However, reported estimates of MAT's sensitivity vary. We evaluated the accuracy of four index tests, MAT on paired samples as well as alternative standards for leptospirosis diagnosis: MAT on single acute-phase samples, polymerase chain reaction (PCR) with the target gene Lfb1, and ELISA IgM with Leptospira fainei serovar Hurstbridge as an antigen.
METHODS
We performed a systematic review of studies reporting results of leptospirosis diagnostic tests. We searched eight electronic databases and selected studies that tested human blood samples and compared index tests with blood culture and/or PCR and/or MAT (comparator tests). For MAT selection criteria we defined a threshold for single acute-phase samples according to a national classification of leptospirosis endemicity. We used a Bayesian random-effect meta-analysis to estimate the sensitivity and specificity of MAT in single acute-phase and paired samples separately, and assessed risk of bias using the Quality Assessment of Studies of Diagnostic Accuracy Approach- 2 (QUADAS-2) tool.
RESULTS
For the MAT accuracy evaluation, 15 studies were included, 11 with single acute-phase serum, and 12 with paired sera. Two included studies used PCR targeting the Lfb1 gene, and one included study used IgM ELISA with Leptospira fainei serovar Hurstbridge as antigen. For MAT in single acute-phase samples, the pooled sensitivity and specificity were 14% (95% credible interval [CrI] 3-38%) and 86% (95% CrI 59-96%), respectively, and the predicted sensitivity and specificity were 14% (95% CrI 0-90%) and 86% (95% CrI 9-100%). Among paired MAT samples, the pooled sensitivity and specificity were 68% (95% CrI 32-92%) and 75% (95% CrI 45-93%) respectively, and the predicted sensitivity and specificity were 69% (95% CrI 2-100%) and 75% (2-100%).
CONCLUSIONS
Based on our analysis, the accuracy of MAT in paired samples was not high, but it remains the reference standard until a more accurate diagnostic test is developed. Future studies that include larger numbers of participants with paired samples will improve the certainty of accuracy estimates.
Topics: Humans; Serogroup; Bayes Theorem; Antibodies, Bacterial; Leptospira; Leptospirosis; Agglutination Tests; Sensitivity and Specificity; Enzyme-Linked Immunosorbent Assay; Immunoglobulin M; Polymerase Chain Reaction
PubMed: 38326762
DOI: 10.1186/s12879-023-08935-0 -
PLoS Neglected Tropical Diseases Mar 2018Visceral leishmaniasis (VL), the most severe form of leishmaniasis, is endemic in Europe with Mediterranean countries reporting endemic status alongside a worrying...
BACKGROUND
Visceral leishmaniasis (VL), the most severe form of leishmaniasis, is endemic in Europe with Mediterranean countries reporting endemic status alongside a worrying northward spread. Serological diagnosis, including immunochromatographic test based on the recombinant antigen rK39 (rK39-ICT) and a direct agglutination test (DAT) based on the whole parasite antigen, have been validated in regions with high VL burden, such as eastern Africa and the Indian subcontinent. To date, no studies using a large set of patients have performed an assessment of both methods within Europe.
METHODOLOGY/PRINCIPAL FINDINGS
We selected a range of clinical serum samples from patients with confirmed VL (including HIV co-infection), Chagas disease, malaria, other parasitic infections and negative samples (n = 743; years 2009-2015) to test the performance of rK39-ICT rapid test (Kalazar Detect Rapid Test; InBios International, Inc., USA) and DAT (ITM-DAT/VLG; Institute of Tropical Medicine Antwerp, Belgium). An in-house immunofluorescence antibody test (IFAT), was included for comparison. Estimated sensitivities for rK39-ICT and DAT in HIV-negative VL patients were 83.1% [75.1-91.2] and 84.2% [76.3-92.1], respectively. Sensitivity was reduced to 67.3% [52.7-82.0] for rK39 and increased to 91.3% [82.1-100.0] for DAT in HIV/VL co-infected patients. The in-house IFAT was more sensitive in HIV-negative VL patients, 84.2% [76.3-92.1] than in HIV/VL patients, 79.4% [73.3-96.2]. DAT gave 32 false positives in sera from HIV-negative VL suspects, compared to 0 and 2 for rK39 and IFAT, respectively, but correctly detected more HIV/VL patients (42/46) than rK39 (31/46) and IFAT (39/46).
CONCLUSIONS/SIGNIFICANCE
Though rK39-ICT and DAT exhibited acceptable sensitivity and specificity a combination with other tests is required for highly sensitive diagnosis of VL cases in Spain. Important variation in the performance of the tests were seen in patients co-infected with HIV or with other parasitic infections. This study can help inform the choice of serological test to be used when screening or diagnosing VL in a European Mediterranean setting.
Topics: Adult; Agglutination Tests; Antibodies, Protozoan; Chromatography, Affinity; Endemic Diseases; Female; Humans; Leishmania donovani; Leishmaniasis, Visceral; Male; Middle Aged; Predictive Value of Tests; Reagent Kits, Diagnostic; Sensitivity and Specificity; Spain; Young Adult
PubMed: 29494596
DOI: 10.1371/journal.pntd.0006277 -
BMJ (Clinical Research Ed.) Oct 2006To compare the performance of the direct agglutination test and rK39 dipstick for the diagnosis of visceral leishmaniasis. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To compare the performance of the direct agglutination test and rK39 dipstick for the diagnosis of visceral leishmaniasis.
DATA SOURCES
Medline, citation tracking, January 1986 to December 2004. Selection criteria Original studies evaluating the direct agglutination test or the rK39 dipstick with clinical visceral leishmaniasis as target condition; adequate reference classification; and absolute numbers of true positive, true negative, false positive, and false negative observations available or derivable from the data presented.
RESULTS
30 studies evaluating the direct agglutination test and 13 studies evaluating the rK39 dipstick met the inclusion criteria. The combined sensitivity estimates of the direct agglutination test and the rK39 dipstick were 94.8% (95% confidence interval 92.7% to 96.4%) and 93.9% (87.7% to 97.1%), respectively. Sensitivity seemed higher and more homogenous in the studies carried out in South Asia. Specificity estimates were influenced by the type of controls. In phase III studies carried out on patients with clinically suspected disease, the estimated specificity of the direct agglutination test was 85.9% (72.3% to 93.4%) and of the rK39 dipstick was 90.6% (66.8% to 97.9%).
CONCLUSION
The diagnostic performance of the direct agglutination test and the rK39 dipstick for visceral leishmaniasis is good to excellent and seem comparable.
Topics: Agglutination Tests; Enzyme-Linked Immunosorbent Assay; False Negative Reactions; False Positive Reactions; Humans; Leishmaniasis, Visceral; Sensitivity and Specificity
PubMed: 16882683
DOI: 10.1136/bmj.38917.503056.7C -
Indian Journal of Medical Microbiology 2014Leptospirosis is a potentially fatal bacterial disease that mimics many diseases; therefore, laboratory confirmation is pivotal. Though microscopic agglutination test...
BACKGROUND AND OBJECTIVES
Leptospirosis is a potentially fatal bacterial disease that mimics many diseases; therefore, laboratory confirmation is pivotal. Though microscopic agglutination test (MAT) is accepted as World Health Organisation (WHO) reference test, it has got many pitfalls such as being hazardous, tedious, cumbersome and expensive. Counterimmunoelectrophoresis (CIE) is popularly used for diagnosing many infectious diseases but rarely for Leptospirosis. The aim of this study is to find suitability of CIE for the routine laboratory diagnostic purposes.
MATERIALS AND METHODS
Repeat sampling (paired sera) was possible from 401 subjects of which 181 were in-patients of Salem Government General and Private Hospitals and the remaining 220 MAT negative healthy College students gave their consent for the study. All the 802 sera samples were collected from January 2009 to November 2012 and subjected to the present study. After carrying out MAT and CIE on the suspected and control samples, a comparative evaluation was conducted. McNemars test method was used to find out the significant difference between the two tests in the early diagnosis.
RESULT
The sensitivity, specificity, Positive Predictive value (PPV), Negative Predictive value (NPV) and Efficiency test for CIE were 96.80%, 89.28%, 95.23%, 92.59% and 94.47%, respectively. The corresponding values for MAT were 95.90%, 89.83%, 95.08%, 91.37% and 93.92%, respectively. There was no significant difference between MAT and CIE at 95% and 99% confidence intervals according to McNemars test. P value in the early stage of illness was greater for CIE than MAT when Polymerase Chain Reaction (PCR) was used as Gold Standard of diagnosis.
INTERPRETATION AND CONCLUSION
It was concluded that the CIE could be advantageous over MAT due to its safety, rapidity, simplicity, economic and easy for large number of samples. It can answer little earlier than MAT and found as reliable as that of MAT. Since both the tests had shown similar efficacies in the later stage of the illness, the importance could be given to CIE due to early diagnosis.
Topics: Adolescent; Agglutination Tests; Child; Child, Preschool; Clinical Laboratory Techniques; Counterimmunoelectrophoresis; Female; Humans; Infant; Leptospirosis; Male; Predictive Value of Tests; Sensitivity and Specificity
PubMed: 24399383
DOI: 10.4103/0255-0857.124291 -
The Tohoku Journal of Experimental... Apr 2023The incidence of Brucella canis (B. canis) in humans is unknown in Northern Cyprus. In this study, we investigated the prevalence of B. canis and Brucella abortus (B....
The incidence of Brucella canis (B. canis) in humans is unknown in Northern Cyprus. In this study, we investigated the prevalence of B. canis and Brucella abortus (B. abortus) infection in human sera and evaluated the results obtained by agglutination-based techniques using standardized antigens made from B. canis comparatively. All of the subjects were negative in terms of Rose-Bengal plate test. Undiluted serum samples were initially screened by rapid slide agglutination test (RSAT), and those which were found positive were retested in the dilution of 1/25-1/200. Confirmation of the positive results was performed by using 2-mercaptoethanol standard agglutination test (SAT). The test antigen was prepared from the less mucoid M (-) variant of B. canis, and 1/1,048 titered dog antiserum was used as positive control. In 225 serum samples, 3.6% (8/225) was positive by B. canis M (-) RSAT, 4.4 % (10/225) was positive by B. canis M (-) indirect enzyme-linked immunosorbent assay (iELISA). 5.3% (12/225) was positive by B. abortus S99 RSAT and 9.8% (22/225) was positive by B. abortus S99 iELISA. Nine samples were positive by both B. abortus S99 RSAT and B. abortus S99 iELISA. Seven samples were positive by both B. canis M (-) RSAT and B. canis M (-) iELISA. One patient was positive by all methods. It is important to evaluate patient samples with RSAT and iELISA. Until the notification system gives better results to the Ministry of Health, in order to reach the real data for Northern Cyprus, multicenter prevalence determination studies should be done for future.
Topics: Humans; Animals; Dogs; Brucella canis; Brucella abortus; Brucellosis; Cyprus; Antigens, Bacterial; Antibodies, Bacterial; Enzyme-Linked Immunosorbent Assay; Agglutination Tests
PubMed: 36384858
DOI: 10.1620/tjem.2022.J096 -
PloS One 2015Leptospirosis is diagnosed on clinical grounds, and confirmed by microscopic agglutination test (MAT). IgM-ELISA (Serion-Virion) and immunochromatography test... (Comparative Study)
Comparative Study
BACKGROUND
Leptospirosis is diagnosed on clinical grounds, and confirmed by microscopic agglutination test (MAT). IgM-ELISA (Serion-Virion) and immunochromatography test (Leptocheck-WB) are two immunodiagnostic assays for leptospirosis. Their sensitivity, specificity and applicability in Sri Lanka have not been systematically evaluated.
METHODS
Clinically diagnosed leptospirosis patients (n = 919) were recruited from three hospitals in the Western Province of Sri Lanka, during June 2012 to December 2013. MAT, IgM-ELISA and Leptocheck-WB were performed on all patient sera. MAT titer of ≥ 400 in single sample, four-fold rise or seroconversion ≥ 100 in paired samples were considered as positive for MAT. For diagnostic confirmation, MAT was performed during both acute and convalescent phases. Anti-leptospiral IgM ≥ 20 IU/ml and appearance of a band in the test window were considered as positive for IgM-ELISA and Leptocheck-WB test respectively. Patients with an alternative diagnosis (n = 31) were excluded. Data analysis was performed using two methods, i) considering MAT as reference standard and ii) using Bayesian latent class model analysis (BLCM) which considers each test as imperfect.
RESULTS
MAT, IgM-ELISA and Leptocheck-WB positivity were 39.8%, 45.8% and 38.7% respectively during the acute phase. Acute-phase MAT had specificity and sensitivity of 95.7% and 55.3% respectively, when compared to overall MAT positivity. IgM-ELISA and Leptocheck-WB had similar diagnostic sensitivity when compared with acute-phase MAT as the gold standard, although IgM-ELISA showed higher specificity (84.5%) than Leptocheck-WB (73.3%). BLCM analysis showed that IgM-ELISA and Leptocheck-WB had similar sensitivities (86.0% and 87.4%), while acute-phase MAT had the lowest sensitivity (77.4%). However, acute-phase MAT had high specificity (97.6%), while IgM-ELISA and Leptocheck-WB showed similar but lower specificity (84.5% and 82.9%).
CONCLUSIONS
Both IgM-ELISA and Leptocheck-WB shows similar sensitivities and specificities. IgM-ELISA may be superior to MAT during the acute phase and suitable for early diagnosis of leptospirosis. Leptocheck-WB is suitable as a rapid immunodiagnostic screening test for resource limited settings.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Agglutination Tests; Antibodies, Bacterial; Chromatography, Affinity; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoglobulin M; Leptospira; Leptospirosis; Male; Middle Aged; Reagent Kits, Diagnostic; Sensitivity and Specificity; Young Adult
PubMed: 26086800
DOI: 10.1371/journal.pone.0129236 -
Transactions of the Royal Society of... Jan 2011Leishmaniasis is a vector-borne disease with up to 350 million people at risk of infection worldwide. Among its different clinical manifestations, visceral is the most... (Review)
Review
Leishmaniasis is a vector-borne disease with up to 350 million people at risk of infection worldwide. Among its different clinical manifestations, visceral is the most severe form. Since clinical features of visceral leishmaniasis (VL) mimic several other common diseases, accurate diagnosis is crucial as the treatment is associated with significant toxicity. Invasive and risky techniques involving demonstration of the parasites in stained preparations from splenic and bone marrow aspirate is still the gold standard for VL diagnosis. Serological tests using rK39 in ELISA or rapid immunochromatographic format, Direct Agglutination Test (DAT), immunoblotting have issues related to a significant proportion of asymptomatic individuals being positive with these tests and their inability to diagnose relapses as these remain positive for several months to years after cure. PCR is the most common molecular technique successfully used for diagnosis and differentiation of species. Through this review we focus extensively on the comparative utilities of the various diagnostic tools currently available for VL, describing in depth their advantages and disadvantages, addressing the recent advances attained in the field. A simple, rapid, non invasive, accurate and cost effective marker of active VL, which can be used in field conditions, is necessary to improve diagnosis of VL.
Topics: Agglutination Tests; Animals; Antigens, Protozoan; Enzyme-Linked Immunosorbent Assay; Humans; Leishmaniasis, Visceral; Polymerase Chain Reaction; Sensitivity and Specificity; Serologic Tests
PubMed: 21074233
DOI: 10.1016/j.trstmh.2010.09.006 -
Journal of Clinical Pathology May 1989The performance of a direct agglutination test for the detection of toxoplasma specific IgG immunoglobulin was compared with that of the latex agglutination test. The... (Comparative Study)
Comparative Study
The performance of a direct agglutination test for the detection of toxoplasma specific IgG immunoglobulin was compared with that of the latex agglutination test. The direct agglutination test was less sensitive but more specific than the latex agglutination test. Quantitative results were not directly comparable, reflecting the different antibody profiles detected in each assay. The direct agglutination test represents an alternative to the latex agglutination test as a screening test for toxoplasmosis. Patients at risk of life threatening infection require detailed serological examination using additional assays.
Topics: Agglutination Tests; Animals; Antibodies, Protozoan; Humans; Immunoglobulin G; Latex Fixation Tests; Toxoplasma; Toxoplasmosis
PubMed: 2732349
DOI: 10.1136/jcp.42.5.536