A comparison of three column agglutination tests for red blood cell alloantibody identification.

OBJECTIVE: Commercial kits of column tests for pre-transfusion testing have progressively replaced conventional tube tests in most laboratories. Aim of this study was to compare three commercial test cell panels for the identification of irregular red blood cell (RBC) alloantibodies. Overall, 44 samples with a positive indirect antiglobulin test (IAT) by routine testing were used for comparison of following panels: Ortho RESOLVE® panelC (Ortho Clinical Diagnostics (OCD), Milan, Italy), ID-DiaPanel(-P) (Bio-Rad Laboratories, CA, USA) and Identisera Diana(P) (Grifols, Barcelona, Spain). Column agglutination techniques were used, with microtubes containing either microgel (Bio-Rad/Grifols) or glass bead microparticles (Ortho). RESULTS: Alloantibody identification was possible in 38 samples, of which identical identification was shown in 33 samples by all methods. The remaining samples showed differences between certain methods, with the gel card system being superior to the glass card system for analyzing stored samples Considering that not all samples were evaluated in all three methods, the concordance rate reached 100% between Bio-Rad and Grifols, 90.5% between Bio-Rad and OCD, 86.5% between OCD and Grifols and 90.5% between all methods. Although differences in sensitivities were seen for specific antibodies, the three methods showed comparable performance for the identification of RBC alloantibodies.

ELISA is superior to bacterial culture and agglutination test in the diagnosis of brucellosis in an endemic area in China.

BACKGROUND: Brucellosis is endemic in many areas in China. The current diagnosis of Brucellosis predominantly relies on the traditional bacterial culture and serum agglutination test. In this study, we aimed to explore the value of ELISA in the diagnosis of Brucellosis in Chinese population. METHODS: We recruited 235 patients with a diagnosis of Brucellosis at different clinical stages: 117 in acute, 78 in subacute, and 40 in chronic. We also recruited 248 control patients who presented with similar clinical symptoms but with a different diagnosis other than Brucellosis. In addition, 90 healthy volunteers were also recruited. Bacterial culture, agglutination test and ELISA assay were performed to detect Brucella spp. RESULTS: Among 235 patients with Brucellosis, 51 (21.7%) was positive for bacterial culture, 150 (63.8%) were positive by agglutination test, and 232 (98.7%) were positive by ELISA (IgG and/or IgM). When we stratified the patients based on the disease stages (acute, subacute and chronic), ELISA was the most sensitive method and showed a highest positive rate in all stages. By Receiver Operating Characteristic Curve analysis of ELISA results, we found that measurement of IgG level was superior to measurement of IgM level (AUC, 0.993 versus 0.877). Since the measurement of IgG itself missed rare cases in acute phase, we recommended measuring IgG and IgM simultaneously by ELISA for the diagnosis of Brucellosis. In term of the specificity of ELISA in the diagnosis of Brucellosis, our study showed that only 1.6% (4/248) non-Brucellosis patients were positive by ELISA; all positive cases were IgM only and none showed positive IgG. Similar results were found in healthy volunteers. In summary, our study concluded that ELISA is the most sensitive and specific method to detect Brucellosis in Chinese population. CONCLUSIONS: ELISA assay is sensitive, fast, and convenient to detect Brucellosis. It shows the high sensitivity and specifity and should be used as a routine lab test when Brucellosis is suspected in clinical practice.

Novel Example of a Direct-Agglutinating Anti-Ku.

BACKGROUND: Several Kell-system antibodies are known to cause direct agglutination. Also, some specificities, such as anti-Ku, have been reported to react only via the indirect antiglobulin test (IAT). METHODS: Herein, we describe the case of a 61-year-old alloimmunized white woman who presented to an outside hospital with a gastrointestinal (GI) bleed and a "possible anti-Ku" was reported with 3+ reactivity at PEG-IAT and at Ficin-IAT; in addition to an unidentified cold antibody. Subsequently, when the patient presented to a second outside hospital, an anti-Ku that caused 3+ to 4+ reactions at saline-immediate spin (IS) was identified. The reactivity was evaluated with 0.01-M dithiothreitol (DTT) treatment of the plasma. RESULTS: It was determined that the strong agglutination with saline-IS was caused by immunoglobulin (Ig)M anti-Ku. CONCLUSION: To our knowledge, this is the first reported case of an IgM anti-Ku.

Performance of serological tests available in Brazil for the diagnosis of human visceral leishmaniasis.

BACKGROUND: Visceral leishmaniasis (VL) is the most severe form of leishmaniasis and is potentially fatal if not diagnosed and treated. Accurate and timely diagnosis is considered one of the pillars needed for the reduction in disease-related lethality. Brazil is currently one of the three eco-epidemiological hotspots for this disease. Several serological tests are commercially available in this country for VL diagnosis, although information on the performance of these tests is fragmented and insufficient. The aim of this study was to directly compare the performance of six commercial kits: three enzyme-linked immunosorbent assays (ELISAs), two immunofluorescence antibody tests (IFATs), one immunochromatographic test (ICT), besides one ICT, currently not commercially available in Brazil and one in-house direct agglutination test (DAT-LPC), not yet marketed. METHODOLOGY/PRINCIPAL FINDINGS: A panel of 236 stored samples from patients with clinically suspected VL, including 77 HIV-infected patients, was tested. IT-LEISH and DAT-LPC showed the highest accuracy rate among the non-HIV-infected patients, 96.2% [CI95%: 92.8-99.7%] and 95.6% [CI95%: 91.9-99.3%], respectively. For the ELISA tests evaluated, the maximum accuracy was 91.2%, and in the inter HIV-status group analysis, no significant differences were observed. For both IFATs evaluated, the maximum accuracy was 84.3%, and a lower accuracy rate was observed among the HIV-infected patients (p = 0.039) than among the non-HIV-infected patients. The DAT-LPC was the most accurate test in the HIV-infected patients (p≤0.115). In general, no significant difference in accuracy was observed among the VL-suspected patients stratified by age. CONCLUSIONS/SIGNIFICANCE: In summary, the differences in the performance of the tests available for VL in Brazil confirm the need for local studies before defining the diagnostic strategy.

Bayesian Evaluation of Three Serological Tests for Detecting Antibodies against Brucella spp. among Humans in the Northwestern Part of Ecuador.

Brucellosis is an important but neglected zoonosis that causes serious economic losses both in livestock and human populations. The aim of the present study was to estimate the true prevalence of brucellosis together with diagnostic sensitivity and specificity of three serological tests in humans of the northwestern part of Ecuador using a Bayesian approach adjusted for the dependencies among the multiple tests to avoid any misinterpretation. In addition, the causal agent responsible for human brucellosis was also identified. Using a total of 3,733 samples collected from humans in this area between 2006 and 2008, the prevalence of human brucellosis and the diagnostic test characteristics of the Rose Bengal fast agglutination test (RBT), Wright's slow agglutination test with ethylenediaminetetraacetic acid disodium salt dehydrate (EDTA) (SAT-EDTA), and indirect ELISA (iELISA) were estimated using a Bayesian approach. The estimated true prevalence of human brucellosis was 1% (credibility interval: 0.4-1.6). The sensitivities of iELISA and RBT were higher than and similar (95.1% and 95.0%, respectively) to those of SAT-EDTA (60.8%). Even though all tests indicated a high specificity (> 99.0%), the specificity of SAT-EDTA was highest (99.9%). The circulating strain in this study area was identified to be Brucella abortus biotype 4 based on culture and microbiological characterization. The RBT and the iELISA are recommended for estimating the true prevalence of human brucellosis and/or for surveillance programs following their high sensitivities and specificities. The proposed strategy supports evidence-based medicine for clinicians and policy-makers to ensure appropriate preventive and control program of brucellosis worldwide.

The Unknown Nature of the Antigen in the Direct Agglutination Test for Visceral Leishmaniasis Hampers Development of Serodiagnostic Tests.

Current diagnostic tests for visceral leishmaniasis (VL) are either not adapted for use in resource-poor settings or are insufficiently accurate in Eastern Africa. Only the direct agglutination test (DAT), based on whole Leishmania promastigotes, is highly reliable in all endemic regions, but its implementation is hampered by the need for a cold chain, minimal laboratory conditions, and long incubation times. Integrating the DAT antigen(s) in an immunochromatographic rapid diagnostic test (RDT) would overcome these disadvantages. Unfortunately, the identity of the DAT antigen(s) involved in the agglutination reaction is unknown. For this study, we reviewed all publications that might shed some light on this issue. We conclude that the DAT antigen is a mixture of Leishmania-specific epitopes of protein, carbohydrate, and lipid nature. To develop an accurate RDT for VL diagnosis in Eastern Africa, we suggest to complement the classical protein antigen discovery with approaches to identify carbohydrate and lipid epitopes.

Comparison of the tube test and column agglutination techniques for anti-A/-B antibody titration in healthy individuals.

BACKGROUND AND OBJECTIVES: Determination of the anti-A/-B titre pre- and post-transplantation is beneficial for treatment selection. Currently, the recommended method for antibody titration is the tube test (TT) assay. Dithiothreitol (DTT) is used for IgM antibody inactivation. Recently, a fully automated antibody titration assay using the column agglutination technique (CAT) was developed (auto-CAT). Our aim was to compare the auto-CAT and TT techniques for ABO antibody titration, to evaluate the effectiveness of DTT-treated plasma for use with auto-CAT and to define the cut-off value for antibody titration by auto-CAT. MATERIALS AND METHODS: We enrolled 30 healthy individuals, including 10 each for blood types A, B and O. We performed antibody titre measurement using the TT technique and auto-CAT simultaneously. Auto-CAT uses the bead column agglutination technology. RESULTS: With the auto-CAT cut-off value set to weak (w)+ with DTT treatment plasma, the concordance rate was 45%, and the weighted kappa value between TT and auto-CAT results was 0·994 in all subjects. Furthermore, there was a significant positive correlation between the anti-A/-B titre results obtained using the TT technique and auto-CAT in all blood types. Moreover, a positive bias (falsely elevated end-points due to agglomeration of A/B cells) was not observed in auto-CAT testing using DTT-treated plasma. CONCLUSION: Our results show that 1+ agglutination using the TT technique is equivalent to w+ agglutination obtained using auto-CAT. We recommend that DTT may be used with auto-CAT to measure antibody titres. Thus, we suggest that auto-CAT is useful for antibody titration in routine examination.

Leptospirosis: a diagnostic conundrum.

Leptospirosis is a serious public health concern worldwide. It is highly endemic in the Andaman Islands and its prevalence is increasing in other Indian states. Clinical features are non-specific and diagnosis relies on laboratory confirmation. The gold standard is microscopic agglutination testing, but this is not widely available. Real-time polymerase chain reaction testing of LipL32 antigen provides the earliest detection of pathogenic Leptospira in the body. We found it to be 100% specific, but it should be used in the first 10 days of illness for reliable results.

An evaluation of serological tests in the diagnosis of bovine brucellosis in naturally infected cattle in KwaZulu-Natal province in South Africa.

The diagnostic sensitivity (DSe) of the Rose Bengal test (RBT), the complement fixation test (CFT), the serum agglutination test (SAT), the competitive enzyme-linked immunosorbent assay (cELISA) and the indirect ELISA (iELISA) were determined in naturally infected cattle in KwaZulu-Natal province of South Africa with known infectious status from culture (gold standard). Natural brucellosis infection status of animals was determined by culturing and identification of Brucella abortus biovar 1 from abomasal fluid, milk, hygroma fluid, lymph nodes or uterine discharges samples. The diagnostic specificity (DSp) of the tests mentioned above was determined using samples from known negative herds. There was no statistically significant difference between the tests in their ability to diagnose brucellosis. The RBT and iELISA had the highest DSe of 95.8%, whereas RBT and CFT had the highest DSp of 100%. In South African laboratories, the RBT and CFT serological tests are used, because of the cost efficacy of CFT when compared to the less labour intensive but more expensive iELISA.

Toxoplasma gondii in stranded marine mammals from the North Sea and Eastern Atlantic Ocean: Findings and diagnostic difficulties.

The occurrence of the zoonotic protozoan parasite Toxoplasma gondii in marine mammals remains a poorly understood phenomenon. In this study, samples from 589 marine mammal species and 34 European otters (Lutra lutra), stranded on the coasts of Scotland, Belgium, France, The Netherlands and Germany, were tested for the presence of T. gondii. Brain samples were analysed by polymerase chain reaction (PCR) for detection of parasite DNA. Blood and muscle fluid samples were tested for specific antibodies using a modified agglutination test (MAT), a commercial multi-species enzyme-linked immunosorbent assay (ELISA) and an immunofluorescence assay (IFA). Out of 193 animals tested by PCR, only two harbour porpoise (Phocoena phocoena) cerebrum samples, obtained from animals stranded on the Dutch coast, tested positive. The serological results showed a wide variation depending on the test used. Using a cut-off value of 1/40 dilution in MAT, 141 out of 292 animals (41%) were positive. Using IFA, 30 out of 244 tested samples (12%) were positive at a 1/50 dilution. The commercial ELISA yielded 7% positives with a cut-off of the sample-to-positive (S/P) ratio≥50; and 12% when the cut-off was set at S/P ratio≥20. The high number of positives in MAT may be an overestimation due to the high degree of haemolysis of the samples and/or the presence of lipids. The ELISA results could be an underestimation due to the use of a multispecies conjugate. Our results confirm the presence of T. gondii in marine mammals in The Netherlands and show exposure to the parasite in both the North Sea and the Eastern Atlantic Ocean. We also highlight the limitations of the tests used to diagnose T. gondii in stranded marine mammals.

Serodiagnosis of bovine trypanosomosis caused by non-tsetse transmitted Trypanosoma (Duttonella) vivax parasites using the soluble form of a Trypanozoon variant surface glycoprotein antigen.

Previous studies have shown that a 64-kDa antigen (p64) that was purified from the Venezuelan TeAp-N/D1 isolate of Trypanosoma (Trypanozoon) equiperdum corresponds to the soluble form of its predominant variant surface glycoprotein (VSG), and exhibited cross-reactivity with Trypanosoma (Duttonella) vivax. The course of experimental acute infections of bovines with T. vivax were followed by measuring whole anti-p64 antibodies and specific anti-p64 IgG and IgM antibodies in animal sera by indirect enzyme-linked immunosorbent assay (ELISA). The value of p64 to diagnose bovine trypanosomosis was also examined using 350 sera from healthy and T. vivax-infected cows living in a trypanosomosis-endemic and enzootic stable area, and 48 sera obtained during a trypanosomosis outbreak. Serological assays showed that ∼ 70-80% of the infected sera contained anti-p64 antibodies, based on the comparative immunodetection of the T. equiperdum clarified antigenic fraction used as a reference test. In the absence of a gold standard, Bayesian analysis for multiple testing estimated a sensitivity and specificity of 71.6% and 98.8%, respectively, for the indirect ELISA using p64 as antigen. An apparent prevalence of 37.7% for bovine trypanosomosis infection was also estimated with a Bayesian approach when the p64 ELISA test was used. Employing blood from acute infected cows, the indirect ELISA response against p64 was contrasted with the microhematocrit centrifuge method and analyses by polymerase chain reaction (PCR) using specific primers targeting the inter-specific length variation of the internal transcribed spacer 1 region of the 18S ribosomal gene. The efficiency of p64 for the detection of anti-trypanosome antibodies in acute infected bovines was also corroborated serologically by comparing its response to that of the Indonesian Trypanosoma evansi Rode Trypanozoon antigen type (RoTat) 1.2 VSG, which possesses high specificity and sensitivity. As expected, PCR was the best method to detect parasites and diagnose bovine trypanosomosis; however, a substantial level of concordance (Cohen's κ=0.667) was obtained when serological tests using p64 and RoTat 1.2 VSG were compared. Additionally, an agglutination assay was designed using p64 covalently coupled to carboxylate-modified latex microparticles, which was proven here to be suitable for a fast qualitative diagnosis of bovine trypanosomosis.

Is the microagglutination test (MAT) good for predicting the infecting serogroup for leptospirosis in Brazil?

Leptospirosis is a zoonotic infection caused by pathogenic members of the genus Leptospira spp. Knowledge of the prevalent serovars and their maintenance hosts is essential to understand the disease. The aim of this study was to evaluate the ability of serology by the microscopic agglutination test (MAT) to predict the serogroups compared with results of identification of leptospires in São Paulo, Brazil. MAT correctly assigned the serogroup of the infecting isolate in 49/52 cases (94.23%). The serogroup Icterohaemorrhagiae was the predominant serogroup (88.46%). This study showed the usefulness of the MAT to correctly identify the infecting serogroup with a good overall agreement between the serologically-identified infecting serogroup and by identification of the isolate and can be used in epidemiological surveys in São Paulo. However, it should be complemented by the identification of Leptospira isolates.

Validation of the modified agglutination test for the detection of Toxoplasma gondii in free-range chickens by using cat and mouse bioassay.

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.

[Evaluation of a reduced panel of leptospira strains for microagglutination]. / Evaluación de un panel reducido de cepas de leptospiras para el diagnóstico en humanos por microaglutinación (MAT).

OBJECTIVE: To evaluate if the use of the 19 Leptospira strains panel suggested by the International Leptospirosis Society of World Health Organization for microagglutination allows confirmation of more cases that the 12 strains panel used in Argentina. MATERIALS AND METHODS: Cross-sectional observational study. We studied 441 serum samples corresponding to Argentinean patients with suspected leptospirosis derived during from July to December, 2009 and from January to October, 2013. RESULTS: The same number of positive samples was obtained using the MAT with the 19 or 12 strains. In six cases a serovar of the expanded collection was presumably infecting, but always coagglutinated with strains of the reduced panel. CONCLUSION: In Argentina, the diagnosis of leptospirosis by MAT could be made using the reduced 12 strains panel, obtaining the same result in case detection as using the 19 strains panel. Additional information provided by the use of all strains could be the presumably infecting serogroup.

Evaluación de un panel reducido de cepas de leptospiras para el diagnóstico en humanos por microaglutinación (MAT) / Evaluation of a reduced panel of leptospira strains for microagglutination

Objetivo. Evaluar si el uso del panel de 19 cepas de leptospiras, sugerido por la Sociedad Internacional de Leptospirosis para la microaglutinación (MAT, por sus siglas en inglés), permite mayor confirmación de casos que el de 12 cepas. Material y métodos. Estudio observacional de corte transversal. Se estudiaron 441 muestras de sueros de pacientes de Argentina, derivadas para el diagnóstico de leptospirosis en los periodos de julio de 2009 a diciembre de 2010 y enero a octubre de 2013. Resultados. Se obtuvo el mismo resultado con el panel reducido que con el ampliado. En seis casos resultó presumiblemente infectante algún serovar del panel ampliado, aunque siempre coaglutinando con cepas del reducido. Conclusión. En Argentina, el diagnóstico de leptospirosis por MAT podría continuar realizándose con el panel reducido, lo que reduciría el costo y tiempo de diagnóstico. La información adicional que aportaría el panel ampliado está relacionada con la epidemiología, mediante un mejor conocimiento del serogrupo presumiblemente infectante.

Objective. To evaluate if the use of the 19 Leptospira strains panel suggested by the International Leptospirosis Society of World Health Organization for microagglutination allows confirmation of more cases that the 12 strains panel used in Argentina. Materials and methods. Cross-sectional observational study. We studied 441 serum samples corresponding to Argentinean patients with suspected leptospirosis derived during from July to December, 2009 and from January to October, 2013. Results. The same number of positive samples was obtained using the MAT with the 19 or 12 strains. In six cases a serovar of the expanded collection was presumably infecting, but always coagglutinated with strains of the reduced panel. Conclusion. In Argentina, the diagnosis of leptospirosis by MAT could be made using the reduced 12 strains panel, obtaining the same result in case detection as using the 19 strains panel. Additional information provided by the use of all strains could be the presumably infecting serogroup.

[Comparison of a new and rapid method, Brucella Coombs gel test with the other methods in the serological diagnosis of brucellosis]. / Brusellozun serolojik tanisinda yeni ve hizli bir yöntem olan Brucella Coombs jel testi ile diger yöntemlerin karsilastirilmasi.

Diagnosis of brucellosis basically depends on blood and/or bone marrow culture and demonstration of high titer specific antibody or seroconversion in serum. In routine serological diagnosis of the disease, after screening with Rose Bengal test, the positive samples are studied with standart tube agglutination (STA) test with serial dilutions. However false negative results can be seen in STA test due to the existence of blocking antibodies, this test should be verified with Coombs anti-Brucella (CAB) or immunocapture agglutination (ICA) tests. In recent years Brucella Coombs gel test (ODAK Brucella Coombs Gel Test, Toprak Medikal, Turkey) developed in our country, was available as a new and rapid agglutination based method. The test is performed in vials that contain Coombs antibodies within gel matrix and results are evaluated visually within two hours.The aim of this study was to compare the efficacy of Brucella Coombs gel test (BCGT) with STA, CAB and ICA methods in serological diagnosis of brucellosis. A total of 100 serum samples with suspected brucellosis sent to our laboratory between January 2012-August 2013 in which 31 high positive (≥ 1/160), 23 low positive (≤ 1/80) and 46 negative samples diagnosed with CAB test (Seromed, Turkey) were included in the study. All the samples were studied using titrations with STA (Seromed, Turkey), ICA (Vircell, Spain) and BCGT (Islab, Turkey) methods. With STA, CAB and BCGT tests ≥ 1/160, with ICA test ≥ 1/320 were accepted as positive titers. The correlation between the tests were evaluated with Cohen's kappa (κ) analysis. In our study, seven of the samples yielded positive results with STA, 30 with ICA, and 32 with BCGT. The number of the sera which yielded positive results with all three methods was 28. Two samples positive with CAB and BCGT resulted low titer/negative with ICA, one sample positive with ICA and BCGT resulted low titer/negative with CAB, and one low titer/negative sample with CAB and BCGT yielded positive with ICA test. STA test was not included in the statistical evaluation due to its very low positivity rate. According to the kappa analysis, almost perfect agreement was detected between the other methods (κ= 0.887 for CAB and ICA, κ= 0.977 for CAB and BCGT, κ= 0.907 for ICA and BCGT). In conclusion, BCGT method showed excellent correlation with both CAB and ICA tests; the application of the test was practical; resulted in a short time such as two hours and visually evaluation was determined to be practical compared to other methods. Although BCGT can be recommended for routine diagnostics, evaluation of specificity and sensitivity with comprehensive studies including a greater number of cases and control samples should be considered.

Ability of immunodiagnostic tests to differentiate between dogs naturally infected with Leishmania infantum and Leishmune(®)-vaccinated dogs.

Visceral leishmaniasis (VL) is a serious chronic disease with a lethality rate of up to 10% in humans. In urban areas of Brazil, dogs are the main reservoirs of the etiological agent (Leishmania infantum) of VL, and the Brazilian Ministry of Health recommends the euthanasia of animals that are seropositive in both the immunochromatographic dual path platform rapid test (DPP(®); Bio-Manguinhos) and the enzyme-linked immunosorbent assay (ELISA) with an L. major-like antigen (Bio-Manguinhos). Vaccination is an additional tool in the control of canine VL, but the use of Leishmune(®) (Zoetis Indústria de Produtos Veterinários, São Paulo, SP, Brazil), which contains the fucose mannose ligand (FML) isolated from L. donovani, is not currently recommended by the Brazilian Ministry of Health because vaccinated animals may exhibit positive serology and there are reservations regarding the efficacy of the vaccine. The aims of the present study were: (i) to verify the abilities of the fast agglutination screening test (FAST), the direct agglutination test (DAT), the indirect fluorescent-antibody test (IFAT), the DPP rapid test, and ELISA tests with L. major-like and FML antigens to differentiate between L. infantum-infected and Leishmune(®)-vaccinated dogs, and (ii) to analyze the sensitivities and specificities of the different methods. The reactivities to these tests of Leishmune(®)-vaccinated dogs (n = 71), asymptomatic (n = 20) and symptomatic (n = 20) naturally infected dogs, and unvaccinated healthy control dogs (n = 5) were compared. None of the Leishmune(®)-vaccinated dogs tested seropositive in FAST and DAT, although one dog was reactive to DPP and four dogs to ELISA/L. major-like and IFAT tests. While 69 (97%) of vaccinated dogs reacted to ELISA/FML, only one was seropositive in both ELISA/L. major-like and IFAT tests. Individually, all immunodiagnostic tests presented high specificities and positive likelihood ratios (LR+), and high specificity values were obtained when the tests were considered in pairs. However, sensitivity and LR- values were low for ELISA/L. major-like and IFAT tests individually, and for all pair combinations of tests except for FAST with DPP.

Study of baseline Widal titres in a healthy adult population of Wayanad district, Kerala, India.

The Widal test is still widely used in diagnosing typhoid fever in developing countries. Often, specific chemotherapy is administered based on a single Widal test. Interpretation of a single Widal test, in turn, depends on the baseline agglutinin titres among the local population in that area. Hence, we aimed to find out the baseline titres in our area. A single blood sample was collected from hospital outpatients with non-infectious diseases, the patients being aged above 18 years and residing in Wayanad district continuously for at least 5 years. The test was performed according to the Widal test kit manufacturer's instructions and interpreted using standard guidelines. The baseline titre for Anti TO, TH, AH and BH agglutinins in our area was found to be 1:40, 1:80, 1:40 and 1:40, respectively.

Standardization of ABO antibody titer measurement at laboratories in Korea.

BACKGROUND: Measurement of the ABO antibody (Ab) titer is important in ABO-incompatible transplantation. However, to the best of our knowledge, no standard protocol or external survey program to measure the ABO Ab titer has been established in Korea. We investigated the current status of ABO Ab titer measurements at various laboratories in Korea and the impact of the protocol provided to reduce interlaboratory variations in the methods and results of ABO Ab titers. METHODS: The Korean external quality assessment of blood bank laboratories sent external survey samples with a questionnaire to 68 laboratories across Korea for the measurement of ABO Ab titers in May 2012. After 6 months, a second set of survey samples were sent with a standard protocol to 53 of the previously surveyed laboratories. The protocol recommended incubation at room temperature only and use of the indirect antihuman globulin method for the tube test as well as and the column agglutination test (CAT). RESULTS: Several interlaboratory variations were observed in the results, technical procedures, and methods selected for measurement. We found that 80.4% laboratories hoped to change their protocol to the provisional one. Additionally, CAT showed significantly lower variation among laboratories (P=0.006) than the tube test. CONCLUSIONS: Our study provides baseline data regarding the current status of ABO Ab titer measurement in Korea. The standard protocol and external survey were helpful to standardize the technical procedures and select methods for ABO Ab titer measurement.

Sensitivity and specificity of HAT Sero-K-SeT, a rapid diagnostic test for serodiagnosis of sleeping sickness caused by Trypanosoma brucei gambiense: a case-control study.

BACKGROUND: Human African trypanosomiasis (HAT) is a life-threatening infection affecting rural populations in sub-Saharan Africa. Large-scale population screening by antibody detection with the Card Agglutination Test for Trypanosomiasis (CATT)/Trypanosoma brucei (T b) gambiense helped reduce the number of reported cases of gambiense HAT to fewer than 10 000 in 2011. Because low case numbers lead to decreased cost-effectiveness of such active screening, we aimed to assess diagnostic accuracy of a rapid serodiagnostic test (HAT Sero-K-SeT) applicable in primary health-care centres. METHODS: In our case-control study, we assessed participants older than 11 years who presented for HAT Sero-K-SeT and CATT/T b gambiense at primary care centres or to mobile teams (and existing patients with confirmed disease status at these centres) in Bandundu Province, DR Congo. We defined cases as patients with trypanosomes that had been identified in lymph node aspirate, blood, or cerebrospinal fluid. During screening, we recruited controls without previous history of HAT or detectable trypanosomes in blood or lymph who resided in the same area as the cases. We assessed diagnostic accuracy of three antibody detection tests for gambiense HAT: HAT Sero-K-SeT and CATT/T b gambiense (done with venous blood at the primary care centres) and immune trypanolysis (done with plasma at the Institute of Tropical Medicine, Antwerp, Belgium). FINDINGS: Between June 6, 2012, and Feb 25, 2013, we included 134 cases and 356 controls. HAT Sero-K-SeT had a sensitivity of 0·985 (132 true positives, 95% CI 0·947-0·996) and a specificity of 0·986 (351 true negatives, 0·968-0·994), which did not differ significantly from CATT/T b gambiense (sensitivity 95% CI 0·955, 95% CI 0·906-0·979 [128 true positives] and specificity 0·972, 0·949-0·985 [346 true negatives]) or immune trypanolysis (sensitivity 0·985, 0·947-0·996 [132 true positives] and specificity 0·980, 0·960-0·990 [349 true negatives]). INTERPRETATION: The diagnostic accuracy of HAT Sero-K-SeT is adequate for T b gambiense antibody detection in local health centres and could be used for active screening whenever a cold chain and electricity supply are unavailable and CATT/T b gambiense cannot be done.