Comparative Evaluation of Widal Slide Agglutination Test and Widal Tube Agglutination Test in Diagnosing Enteric Fever among Patients Attending a Tertiary Care Hospital in Western Odisha.

BACKGROUND Enteric fever is a feco-orally transmitted disease with significant morbidity and mortality in India. Isolation of responsible bacteria from blood or bone marrow is the gold standard method for Enteric fever but it is seldom used now a days due to long turnaround time and higher cost. In developing country like India, relatively cheaper Widal test is used to diagnose Enteric fever. There are two methods of Widal test- slide agglutination test and tube agglutination test. The present study was done to compare efficacy of the slide agglutination test and tube agglutination in diagnosing enteric fever.METHODSAn OPD and IPD based cross sectional study was conducted from May 2019 to Oct 2019. A total of 100 patients with clinical suspicion of Enteric fever were included in the study. 15 ml blood was collected. Blood culture of all the samples were also performed by inoculating 10 ml of blood into appropriate blood culture media. Serum was separated from rest of the blood and serum was tested by both slide agglutination test and Widal tube agglutination test.RESULTSAmong 100 patients, slide agglutination test demonstrated positive result in 40(40%) samples and Widal tube agglutination test demonstrated positive result in 27 (27%) samples only. Among 40 samples positive by slide test 12 samples were negative by blood culture test. The slide test had a sensitivity of 93.33%, specificity of 82.86%, positive predictive value of 70% and negative predictive value of 96.67% and tube test had a sensitivity of 86.67%, specificity of 98.57% positive predictive value of 96.30% and negative predictive value of 94.52% considering blood culture as gold standard.CONCLUSIONSDue to higher sensitivity but poor specificity, slide Widal test should be used for rapid screening test and positive samples should be confirmed by Widal tube agglutination test.

Performance and correlation of QuantiFERON-TB Gold, T-SPOT.TB and tuberculin skin test in young children with tuberculosis exposure or tuberculosis disease

To evaluate the performance of interferon gamma release assays and tuberculin skin test in Bacillus Calmette-Guerin vaccinated young children. Methods: A cross-sectional study was conducted in healthy children younger than 5 years who were recently diagnosed with tuberculosis or had recent exposure to active tuberculosis. QuantiFERON-TB Gold, T-SPOT.TB and tuberculin skin test were performed in each patient. Results: Of the 60 children, median age 3.3 years, 17 had tuberculosis and 43 had recent tuberculosis exposure. Overall, 15 (25.0%) children had tuberculin skin test reaction =10 mm; 8 (13.3%) were positive by QuantiFERON-TB Gold In-Tube test, and 12 (20.0%) by T-SPOT.TB. Nineteen (31.7%) children had at least one positive test. There was a moderate agreement between interferon gamma release assays and tuberculin skin test. Conclusions: The positive rates of interferon gamma release assays and tuberculin skin test were low in young children who were infected with tuberculosis, supporting the management strategy of not testing children younger than 5 years. (IGRA) do not react to BCG and most NTM[2], are preferred to TST in older children and adults[3], but may be less reactive in young children with immature T-cell function. Due to the limited knowledge of IGRA in BCG-vaccinated young children, we evaluated the performance and correlation of IGRA tests and TST in young children in a high TB burden setting who received BCG vaccination at birth and recently diagnosed with LTBI, or with active TB.

Performance and correlation of QuantiFERON-TB Gold, T-SPOT.TB and tuberculin skin test in young children with tuberculosis exposure or tuberculosis disease

To evaluate the performance of interferon gamma release assays and tuberculin skin test in Bacillus Calmette-Guerin vaccinated young children. Methods: A cross-sectional study was conducted in healthy children younger than 5 years who were recently diagnosed with tuberculosis or had recent exposure to active tuberculosis. QuantiFERON-TB Gold, T-SPOT.TB and tuberculin skin test were performed in each patient. Results: Of the 60 children, median age 3.3 years, 17 had tuberculosis and 43 had recent tuberculosis exposure. Overall, 15 (25.0%) children had tuberculin skin test reaction =10 mm; 8 (13.3%) were positive by QuantiFERON-TB Gold In-Tube test, and 12 (20.0%) by T-SPOT.TB. Nineteen (31.7%) children had at least one positive test. There was a moderate agreement between interferon gamma release assays and tuberculin skin test. Conclusions: The positive rates of interferon gamma release assays and tuberculin skin test were low in young children who were infected with tuberculosis, supporting the management strategy of not testing children younger than 5 years. (IGRA) do not react to BCG and most NTM[2], are preferred to TST in older children and adults[3], but may be less reactive in young children with immature T-cell function. Due to the limited knowledge of IGRA in BCG-vaccinated young children, we evaluated the performance and correlation of IGRA tests and TST in young children in a high TB burden setting who received BCG vaccination at birth and recently diagnosed with LTBI, or with active TB.

Utility of QuantiFERON®-TB gold In-Tube test compared with tuberculin skin test in diagnosing tuberculosis in Indian children with malnutrition

This prospective cohort study was conducted to compare the accuracy of QuantiFERON®-TB (QFT) Gold In-Tube test and tuberculin skin test (TST) in diagnosing tuberculosis (TB) in predominantly bacille Calmette–Guerin-vaccinated children with a high incidence of malnutrition. The sensitivity of the QFT versus the TST was 69.6% versus 52.9% for WHO-defined TB, with specificity of 86% versus 78.3%, respectively. The concordance of the TST and QFT was 79% overall (? = 0.430), 62.5% in those with WHO-defined TB and 85.7% in those without TB. Majority of the QFT+/TST ? discordance was seen in children with TB, whereas majority of the TST+/QFT ? discordance was seen in those without TB. The TST was more likely to be negative in children with moderate-to-severe malnutrition (P = 0.003) compared to the QFT, which was more likely to be positive in younger children. The significantly better performance of the QFT in malnourished children and those at younger ages supports its use for TB diagnosis in these subpopulations.

Comparison of methodologies for detecting Trypanosoma cruzi parasites by microscopic observation of microhematocrit capillary tubes

Abstract INTRODUCTION: The microscopic examination of microhematocrit tubes (mHCT) has been proposed as the gold standard for acute and congenital Chagas disease diagnosis. We compared different mHCT methodologies detecting T. cruzi parasites in the blood. METHODS: The rotating method, water mount, and immersion oil methods were compared for their suitability, sensitivity, and specificity. RESULTS: The rotating method was easier, faster, and more sensitive than the others with 100% specificity. CONCLUSIONS: The rotating method is feasible for laboratory technicians with standard training in microscopic techniques and is recommended for the diagnosis of acute Chagas disease in primary health care facilities.

A Feasibility Study for Diagnosis of Latent Tuberculosis Infection Using an IGRA Point-of-Care Platform in South Korea

PURPOSE: This study aimed to evaluate ichroma™ IGRA-TB, a novel point-of-care platform for assaying IFN-γ release, and to compare it with QuantiFERON-TB Gold In-Tube (QFT-GIT) for identifying Mycobacterium tuberculosis (M. tb) infection. MATERIALS AND METHODS: We recruited 60 healthy subjects, and blood samples were obtained in QFT-GIT blood collection tubes. The blood collection tubes were incubated at 37℃, and culture supernatant was harvested after 18–24 hours. IFN-γ responses were assessed by the ichroma™ IGRA-TB cartridge and the QFT-GIT IFN-γ enzyme-linked immunosorbent assay. Three active TB patients were recruited as a positive control for M. tb infection. RESULTS: The area under the receiver operating characteristic curve of the ichroma™ IGRA-TB test for differentiating between infected and non-infected individuals was 0.9706 (p < 0.001). Inconsistent positivity between the two tests was found in three participants who showed weak positive IFN-γ responses ( < 1.0 IU/mL) with QFT-GIT. However, the two tests had excellent agreement (95.2%, κ=0.91, p < 0.001), and a very strong positive correlation was observed between the IFN-γ values of both tests (r=0.91, p < 0.001). CONCLUSION: The diagnostic accuracy demonstrated in this study indicates that the ichroma™ IGRA-TB test could be used as a rapid diagnostic method for detecting latent TB infection. It may be particularly beneficial in resource-limited places that require cost-effective laboratory diagnostics.

Modalidades de la Prueba del Tubo Germinal / Modalities of the Germ Tube Test

Las infecciones por levaduras del género Candida, en la actualidad son cada vez más frecuentes, particularmente cuando se presentan condiciones que inmunosuprimen al paciente, como el Síndrome de Inmunodeficiencia Adquirida y el uso de quimioterápicos e inmunomoduladores, entre otros. Candida albicans es la especie del género que se aísla con mayor frecuencia. Entre las pruebas de identificación para las especies de levaduras del género Candida se encuentran la evaluación de las características macroscópicas de las colonias, pruebas físiológicas, como la prueba del tubo germinal, termotolerancia, auxanograma, zimograma, ureasa y resistencia a la cicloheximida, entre otras. De estas, la prueba del tubo germinal es una prueba sencilla y rápida que puede ejecutarse de varias formas. De manera tradicional se ha realizado en tubo y con suero, aunque también se puede realizar en placa. En este trabajo se revisan las diversas formas de realizar esta prueba y se describe una modalidad adicional, producto de la experiencia diaria en el trabajo de laboratorio, con la ventaja del ahorro de material de vidrio y tiempo.

At the present time, the infections by yeasts of the genera Candida, are more and more frequent, particularly when exists inmunosuprimen conditions, like the Acquired Immunodeficiency Syndrome, the use of quimioterapics and inmunomodulators, among others. Candida albicans is the species most frequently isolated from clinical samples. Among the identification tests of the yeasts species of the genera Candida are the evaluation of colony characteristics, physiological and biochemical tests like the germ tube, termotolerancy, auxonogram, zimogram, urease, resistance to cicloheximide, among others. The germ tube test is a simple and fast test, of which several forms exist to carry out it. The traditional way has been made in tube, with serum, although it´s possible to be made in plate. Here we present the modality to directly make the test of the germ tube between slide and slide cover, with advantage of time saving and glass material saving.

Appropriate Condition of Germ Tube Formation as Presumptive Identification Test for Candida albicans / 대한의진균학회지

BACKGROUND: Candida albicans is the most prevalent species found in human yeast infections. The germ tube test is still frequently used for its rapid presumptive identification. Recently Candida dubliniensis as well as C. albicans has been reported to form germ tubes. OBJECTIVE: The purpose of this study was to evaluate the germ tube test at various conditions for rapid presumptive identification of C. albicans. METHODS: C. albicans ATCC 14053, C. albicans ATCC 18804, C. dubliniensis ATCC MYA 646, and C. dubliniensis KCTC 17427 were tested. Human pooled serum (HPS), HBV, HCV infected patient serum, fetal bovine serum (FBS) and rabbit serum (RS) were used for germ tube test. The germ tube formation was evaluated at different keeping condition of various sera, after mixing with 5 different bacterial suspensions and at various incubation conditions. RESULTS: The germ tube formation of C. albicans was more in the RS or FBS than in the HPS. For the various sera fresh sample was always the best expression of germ-tube forming ability. In the HCV infected patient serum and mixing with Pseudomonas aeruginosa germ tube formation was suppressed. C. dubliniensis did not form germ tube in the HPS, only formed in the FBS or RS. CONCLUSION: For rapid presumptive identification of C. albicans not C. dubliniensis the best selection of serum is the fresh HPS. We recommend the examination with isolated colony free from bacteria after incubation for 2 to 3 hours.

Rapid Identification of Candida albicans by 'Spiking' on Blood and Chocolate Agar Plates / 대한임상미생물학회지

BACKGROUND: Colonial morphology of Candida albicans known as 'spiking' on a primary isolation blood agar plate (BAP) allows rapid and presumptive identification of C. albicans. We evaluated the 'spiking' appearance to identify C. albicans. METHODS: A total of 144 fully identified clinical isolates of yeasts and 10 type strains of yeasts were tested. All isolates obtained from the 5% CO2 incubation on BAP and chocolate agar plate (CHOC) were macroscopically examined for the presence of an irregular margin (spiking). The germ tube test was performed by incubating test organisms in 0.5 mL of pooled human sera. RESULTS: The sensitivity for BAP-spiking, CHOC-spiking and germ tube test were 93.7%, 91.1%, and 98.7%, respectively. The specificity for three methods was 100%. CONCLUSION: Use of the spiking identification on BAP can be useful for the economic and rapid presumptive identification of C. albicans in routine laboratories.

Unexpected Antibody Positivity with the Use of the LISS/Coombs Gel Test / 대한임상병리학회지

BACKGROUND: There is a recent trend of increased use of the gel test for the detection of unexpected antibodies (Abs) because of its simplicity and ease with which definitive interpretation can be made. However, because of the low insurance payments in Korea, only the LISS/Coombs card is used and thus the detection rate of the cold Abs has decreased. We have studied the detection rates of the Abs in patients by using the LISS/Coombs gel test and thus evaluated the clinical usefulness of the LISS/Coombs gel test. METHODS: Abs screening tests have been carried out using the DiaMed(TM) LISS/Coombs gel card test (Murten, Switzerland) on 14,942 patients for whom blood transfusions were ordered between July 1, 1997 and March 31, 2001. When the test for Abs was positive, Ab identification tests were further carried out with the DiaMed(TM) LISS/Coombs gel card and the ID-DiaPanel 1-11. RESULTS: Eighty-one out of 14,942 patients (0.54%) revealed positive results. Of these, 15 showed anti-E, 5 showed anti-E+c, 4 showed anti-C, 3 showed anti-D, 2 showed anti-Jk(a), 1 each showed anti-c, anti-M, anti-Lu(a), and anti-K Abs. CONCLUSIONS: Although the detection rate for the cold Abs of the LISS/Coombs gel test was low, it is considered to be highly useful because of the high detection rate for the clinically important warm Abs, the simplicity in carrying out the test, and the easy readability of test results.

Comparison of Murex Candida albicans CA50 with the Germ Tube Test for Presumptive Identification of Candida albicans / 대한임상병리학회지

BACKGROUND: Rapid and reliable identification of Candida albicans becomes more important because the incidence of yeast infections has increased in recent years. Murex C. albicans 50(CA50) assay was developed for rapid and presumptive identification of C. albicans. We evaluated the CA50 assay to identify C. albicans. METHOD: Seventy four yeast isolates from clinical specimens were tested with CA50 and germ tube test. They were identified to species level by API 20C and chlamydospore agar test. RESULT: Of the 74 isolates, 52 were C. albicans and 22 were non-albicans Candida. The sensitivity and specificity for CA50 were 88.5% and 86.4%, respectively. The sensitivity and specificity of the germ tube test using human serum were 88.5% and 90.9% respectively, and those using fetal bovine serum(FBS) were 92.3% and 90.9% respectively. CONCLUSION: CA50 was a rapid and easy-to-perform test, and it was comparable to germ tube test in regard of sensitivity and specificity.