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The Cochrane Database of Systematic... Jun 2014The diagnosis of visceral leishmaniasis (VL) in patients with fever and a large spleen relies on showing Leishmania parasites in tissue samples and on serological tests.... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The diagnosis of visceral leishmaniasis (VL) in patients with fever and a large spleen relies on showing Leishmania parasites in tissue samples and on serological tests. Parasitological techniques are invasive, require sophisticated laboratories, consume time, or lack accuracy. Recently, rapid diagnostic tests that are easy to perform have become available.
OBJECTIVES
To determine the diagnostic accuracy of rapid tests for diagnosing VL in patients with suspected disease presenting at health services in endemic areas.
SEARCH METHODS
We searched MEDLINE, EMBASE, LILACS, CIDG SR, CENTRAL, SCI-expanded, Medion, Arif, CCT, and the WHO trials register on 3 December 2013, without applying language or date limits.
SELECTION CRITERIA
This review includes original, phase III, diagnostic accuracy studies of rapid tests in patients clinically suspected to have VL. As reference standards, we accepted: (1) direct smear or culture of spleen aspirate; (2) composite reference standard based on one or more of the following: parasitology, serology, or response to treatment; and (3) latent class analysis.
DATA COLLECTION AND ANALYSIS
Two review authors independently extracted data and assessed quality of included studies using the QUADAS-2 tool. Discrepancies were resolved by a third author. We carried out a meta-analysis to estimate sensitivity and specificity of rapid tests, using a bivariate normal model with a complementary log-log link function. We analysed each index test separately. As possible sources of heterogeneity, we explored: geographical area, commercial brand of index test, type of reference standard, disease prevalence, study size, and risk of bias (QUADAS-2). We also undertook a sensitivity analysis to assess the influence of imperfect reference standards.
MAIN RESULTS
Twenty-four studies containing information about five index tests (rK39 immunochromatographic test (ICT), KAtex latex agglutination test in urine, FAST agglutination test, rK26 ICT, and rKE16 ICT) recruiting 4271 participants (2605 with VL) were included. We carried out a meta-analysis for the rK39 ICT (including 18 studies; 3622 participants) and the latex agglutination test (six studies; 1374 participants). The results showed considerable heterogeneity. For the rK39 ICT, the overall sensitivity was 91.9% (95% confidence interval (95% CI) 84.8 to 96.5) and the specificity 92.4% (95% CI 85.6 to 96.8). The sensitivity was lower in East Africa (85.3%; 95% CI 74.5 to 93.2) than in the Indian subcontinent (97.0%; 95% CI 90.0 to 99.5). For the latex agglutination test, overall sensitivity was 63.6% (95% CI 40.9 to 85.6) and specificity 92.9% (95% CI 76.7 to 99.2).
AUTHORS' CONCLUSIONS
The rK39 ICT shows high sensitivity and specificity for the diagnosis of visceral leishmaniasis in patients with febrile splenomegaly and no previous history of the disease, but the sensitivity is notably lower in east Africa than in the Indian subcontinent. Other rapid tests lack accuracy, validation, or both.
Topics: Africa, Eastern; Agglutination Tests; Antigens, Protozoan; Asymptomatic Infections; Biomarkers; Chromatography, Affinity; Clinical Trials, Phase III as Topic; Humans; India; Latex Fixation Tests; Leishmaniasis, Visceral; Nepal; Protozoan Proteins; Sensitivity and Specificity
PubMed: 24947503
DOI: 10.1002/14651858.CD009135.pub2 -
Annals of Tropical Medicine and... Mar 1998Laboratory diagnosis of visceral leishmaniasis (VL) is usually based on the detection of Leishmania amastigotes in samples of bone marrow or splenic aspirate obtained by... (Comparative Study)
Comparative Study
Laboratory diagnosis of visceral leishmaniasis (VL) is usually based on the detection of Leishmania amastigotes in samples of bone marrow or splenic aspirate obtained by invasive procedures. Serological tests serve as a useful adjunct and are especially valuable in early or highly immune cases where amastigotes may be too scanty to be seen easily. The direct agglutination test (DAT) is generally considered the most suitable of the four types of tests currently employed (IFAT, counter immuno-electrophoresis, ELISA and DAT). However, the latex agglutination test (LAT) was recently reported to be a rapid and sensitive screening tool for VL and one which could be carried out at the patient's bedside. Further standardization and evaluation of LAT has now revealed that although it is comparable with DAT and dot-ELISA in terms of sensitivity it is far inferior because of cross-reactivity with other infections. This lack of specificity makes LAT unsuitable for routine diagnosis of VL even though it is rapid and sensitive. DAT still appears to be the best choice as a diagnostic tool, as it is very specific and does not require expensive equipment or reagents or much technical competence and the result can be visually interpreted. These merits make DAT very suitable for the diagnosis of VL in endemic areas of India.
Topics: Agglutination Tests; Enzyme-Linked Immunosorbent Assay; Humans; India; Latex Fixation Tests; Leishmaniasis, Visceral; Sensitivity and Specificity
PubMed: 9625911
DOI: 10.1080/00034989859997 -
Parasitology Mar 2016The modified agglutination test (MAT) is one of the most commonly used tests for the detection of antibodies to Toxoplasma gondii in animal and human sera. The objective...
The modified agglutination test (MAT) is one of the most commonly used tests for the detection of antibodies to Toxoplasma gondii in animal and human sera. The objective of the present study was to evaluate the diagnostic accuracy of the MAT and bioassay in free-range/backyard (FR) chickens (Gallus domesticus). Previously-published T. gondii test results from 2066 chickens from 19 countries were compiled for the present study. The frequency of isolation of T. gondii increased for MAT titres between 1:5 and 1:160, and ranged from 61 to 75% for antibody titres of 1:160, 1:320, and ⩾1:640. Twenty-three cats fed pooled hearts from a total of 802 FR seronegative (MAT, <1:5) chickens from several countries did not excrete oocysts, indicating a high negative predictive value of MAT because FR chickens would have been exposed to many microbes; cats are the most sensitive indicators of T. gondii infection in tissues and can excrete millions of oocysts after ingesting even a few bradyzoites. Of the 29 cats in this study, six cats, fed hearts pooled from 15-122 FR chickens, excreted oocysts; but these identifications were likely related to misidentification or prozone. Results of the present study support the validity of MAT for the detection of T. gondii infection in chickens.
Topics: Agglutination Tests; Animals; Antibodies, Protozoan; Biological Assay; Cats; Chickens; Feces; Mice; Poultry Diseases; Reproducibility of Results; Toxoplasma; Toxoplasmosis, Animal
PubMed: 26625933
DOI: 10.1017/S0031182015001316 -
Journal of Veterinary Science Mar 2007Escherichia coli (E. coli) strains were collected from young diarrheic calves in farms and field. Strains that expressed the K99 (F5) antigen were identified by... (Comparative Study)
Comparative Study
Escherichia coli (E. coli) strains were collected from young diarrheic calves in farms and field. Strains that expressed the K99 (F5) antigen were identified by agglutination tests using reference antibodies to K99 antigen and electron microscopy. The K99 antigen from a selected field strain (SAR-14) was heat-extracted and fractionated on a Sepharose CL-4B column. Further purification was carried out by sodium deoxycholate treatment and/or ion-exchange chromatography. Monoclonal antibodies to purified K99 antigen were produced by the hybridoma technique, and a specific clone, NEK99-5.6.12, was selected for propagation in tissue culture. The antibodies, thus obtained, were affinity-purified, characterized and coated onto Giemsastained Cowan-I strain of Staphylococcus aureus (S. aureus). The antibody-coated S. aureus were used in a coagglutination test to detect K99+ E. coli isolated from feces of diarrheic calves. The specificity of the test was validated against reference monoclonal antibodies used in co-agglutination tests, as well as in ELISA. Specificity of the monoclonal antibodies was also tested against various Gram negative bacteria. The developed antibodies specifically detected purified K99 antigen in immunoblots, as well as K99+ E. coli in ELISA and co-agglutination tests. The co-agglutination test was specific and convenient for large-scale screening of K99+ E. coli isolates.
Topics: Agglutination Tests; Animals; Animals, Newborn; Antibodies, Monoclonal; Antigens, Surface; Bacterial Toxins; Cattle; Cattle Diseases; Chromatography, Gel; Chromatography, Ion Exchange; Chromatography, Liquid; Diarrhea; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Escherichia coli; Escherichia coli Infections; Immunoblotting; Staphylococcus aureus
PubMed: 17322775
DOI: 10.4142/jvs.2007.8.1.57 -
Revue Scientifique Et Technique... Dec 2004The authors reviewed over 50 publications in which the sensitivity and specificity values of assays used for the detection of exposure to Brucella abortus had been... (Comparative Study)
Comparative Study Review
The authors reviewed over 50 publications in which the sensitivity and specificity values of assays used for the detection of exposure to Brucella abortus had been examined. The sum of the sensitivity and specificity values for each test was averaged to give a performance index (PI) and allow for a comparison between the different methodologies. A score of 200 was perfect. Based on the PI, the buffered antigen plate agglutination test (BPAT) rated highest (PI = 193.1) among the conventional tests. This indicates better accuracy than the other conventional tests including the Rose Bengal test (PI = 167.6) and the complement fixation test (PI = 172.5). Overall, the primary binding assays, including the fluorescence polarisation assay (PI = 196.4), the indirect enzyme-linked immunosorbent assay (PI = 189.8) and the competitive enzyme-linked immunosorbent assay (PI = 188.2), were more accurate than the conventional tests, except for the BPAT. In addition, a fee comparison suggested that the primary binding tests were price competitive with conventional tests for the diagnosis of brucellosis and, therefore, had a better combined cost/efficiency rating.
Topics: Agglutination Tests; Animals; Brucella abortus; Brucellosis, Bovine; Cattle; Cost-Benefit Analysis; Enzyme-Linked Immunosorbent Assay; Fluorescence Polarization Immunoassay; Reproducibility of Results; Sensitivity and Specificity; Serologic Tests
PubMed: 15861895
DOI: No ID Found -
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 -
Travel Medicine and Infectious Disease Sep 2010This study aimed to evaluate the performance of a fast agglutination screening test (FAST) for serodiagnosis of human Leishmania infantum infection in Iran. FAST is... (Comparative Study)
Comparative Study
This study aimed to evaluate the performance of a fast agglutination screening test (FAST) for serodiagnosis of human Leishmania infantum infection in Iran. FAST is based on the direct agglutination test (DAT) but combines with a higher parasite concentration and is performed with only one serum dilution. The validity of FAST for the detection of L. infantum infection in the field was compared with the direct agglutination test on 110 confirmed or patients suspected of infection with leishmaniasis, 177 healthy individuals and 41 patients with other infectious diseases who were from northwestern and southern parts of Iran. In this study, we found a 1:1600 cut-off point empirically by seeking the best correlation (90.8) between sera confirmed with visceral leishmaniasis and healthy control sera. A sensitivity of 95.4% (95% CI, 91.4-99.4) and specificity of 88.5% (95% CI, 84.2-92.8) were found with 1:1600 as a cut-off titer when DAT-confirmed cases were compared with the control groups. A good degree of agreement was found between FAST and DAT (90.8%) by Kappa analysis. FAST requires 2 h for reading the results versus the 12-18 h needed for DAT. As FAST is simple, rapid, sensitive and non-invasive and does not require a higher volume of antigens or much expertise, it can be used for screening and serodiagnosis of human L. infantum infection.
Topics: Adolescent; Adult; Agglutination Tests; Child, Preschool; Female; Humans; Iran; Leishmania infantum; Leishmaniasis, Visceral; Male; Reproducibility of Results; Sensitivity and Specificity; Time Factors
PubMed: 20971441
DOI: 10.1016/j.tmaid.2010.09.001 -
Journal of Biological Standardization Oct 1988An agglutination test has been developed for the detection of rabies antibodies after human vaccination. The rabies agglutination test (RAT) is based on the capability... (Comparative Study)
Comparative Study
An agglutination test has been developed for the detection of rabies antibodies after human vaccination. The rabies agglutination test (RAT) is based on the capability of specific antibody to agglutinate sensitized polystyrene (or latex) beads. In the RAT, latex beads were coated, in a first step, with inactivated and purified rabies virus (PV strain adapted and propagated on BHK-21 cells) and, in a second step, with bovine serum albumin. Negative control beads were coated with bovine serum albumin (BSA) only. To test for human antibody, several microliters of serum were mixed on a glass slide with an equal volume of virus-sensitized beads and the mixture was gently agitated. After a few minutes, agglutination was visible with sera which had been characterized as positive by the virus neutralization antibody (VNAb) technique. No agglutination was observed with negative sera tested with virus-coated beads or with positive sera tested with BSA-coated beads. Virus-sensitized beads were agglutinated when the virus neutralizing antibody titres were equal to or greater than 2.5 international units per ml (IU/ml) in human sera. The concordance between the RAT results and VNAb titres was about 97% when 2.5 IU/ml was taken as the cut off value for determining the positive sera with the VNAb technique. The possibility that clinicians might use the RAT as a simple means to determine sero-conversion at the end of the post-exposure treatment of patients is discussed.
Topics: Agglutination Tests; Antibodies, Viral; Evaluation Studies as Topic; Humans; Neutralization Tests; Rabies Vaccines; Rabies virus
PubMed: 3198658
DOI: 10.1016/0092-1157(88)90016-9 -
Clinica Chimica Acta; International... May 1997We compared two tests for bedside C reactive protein (CRP) measurement: the latex agglutination test (LAT) and the fat agglutination test (FAT). FAT is based on the... (Comparative Study)
Comparative Study
We compared two tests for bedside C reactive protein (CRP) measurement: the latex agglutination test (LAT) and the fat agglutination test (FAT). FAT is based on the property of CRP to agglutinate fat emulsions in the presence of CaCl2. The sensitivity, specificity and accuracy of FAT and LAT to detect a CRP > 10 mg/l, determined with radial immunodiffusion (n = 500 pediatric patients, CRP range 0- > 80 mg/l), were 91%, 82% and 90% respectively for FAT and 82%, 95% and 85% for LAT. FAT reagent could be stabilized with NaN3 (0.02%) for at least one year, when stored at 4 degrees C (n = 49). NaN3 (0.02%) had no effect on agglutination of FAT (n = 40). In conclusion, in pediatric patients, FAT is a reliable and cost effective alternative to LAT, if serum samples are used.
Topics: Agglutination Tests; C-Reactive Protein; Calcium Chloride; Child; Emulsions; Humans; Immunodiffusion; Indicators and Reagents; Latex Fixation Tests; Point-of-Care Systems; Sensitivity and Specificity
PubMed: 9201433
DOI: 10.1016/s0009-8981(97)06526-1 -
Zentralblatt Fur Bakteriologie,... Sep 1979A simplified tube O-agglutination test was developed and evaluated for the determination of somatic serogroup (O) antigens of Serratia marcescens. Use was made of... (Comparative Study)
Comparative Study
A simplified tube O-agglutination test was developed and evaluated for the determination of somatic serogroup (O) antigens of Serratia marcescens. Use was made of Tryptic Soy broth (TSB)-grown O-cells that had been boiled for 1 hour; 0.145 M NaCl proved a satisfactory diluent. Various technical parameters of this test were examined as well. Rabbit anti-O immune sera, that had been elicited with 5 x concentrated, TSB-grown, 1 hour-boiled O-cells of all 15 currently employed O-antigen reference strains of S. marcescens yielded satisfactory O-agglutinin titers. The tube O-agglutination test compared favorably with the indirect hemagglutination technic, although the latter technic yielded significantly higher O-agglutinin titers with merely 7 of the 15 O-antigens of S. marcescens. The tube O-agglutination test permitted detection of higher O-agglutinin titers than a microtiter O-agglutination test utilizing O-cells that had been stained with safranin O. Conversely, titers obtained with TTC-stained O-cells in a microtiter agglutination procedure approximated those yielded by the tube O-agglutination test, but O-cells of the various S. marcescens strains were stained nonuniformly by triphenyltetrazolium chloride (TTC). As before, there existed marked serologic cross-reactivity between O-antigens O6 and O14. A new O6 candidate strain, S. marcescens isolate S 1i, serotype O6:H20, was proposed. Contrary to O-agglutinins of human control serum, the O-agglutinins of rabbit anti-O immune sera proved refractory to treatment with 0.1 M of 2-mercaptoethanol (2-ME) and 0.01 M dithiothreitol (DTT) respectively. Dual absorptions of rabbit anti-O immune sera with killed cells of Staphylococcus aureus Cowan I (protein A), failed to significantly reduce O-agglutinin titers, although human IgG and IgM was bound by protein A. It was tentatively concluded that the 2-ME- and DTT-refractory rabbit anti-S. marcescens O-agglutinins resided in the IgM immunoglobulin class.
Topics: Agglutination Tests; Agglutinins; Animals; Antigens, Bacterial; Hemagglutination Tests; Immune Sera; Rabbits; Serotyping; Serratia marcescens
PubMed: 396741
DOI: No ID Found