Subject(s)
DNA, Bacterial , Adult , Arteriovenous Shunt, Surgical , Catheterization, Central Venous , Cross-Sectional Studies , DNA, Bacterial/blood , Endotoxins/blood , Female , Humans , Kidney Failure, Chronic/blood , Kidney Failure, Chronic/therapy , Male , Middle Aged , Renal Dialysis , Time FactorsABSTRACT
BACKGROUND: Serodiagnosis of typhoid fever by Widal test based on demonstrating the presence of agglutinins (antibodies) in the serum of an infected patient, against the H (flagellar) and O (somatic) antigens of Salmonella enterica serotype Typhi has been associated with many debates. This is why the aim of this study was to: (i) Compare the diagnostic accuracy of four different commercial kits used to perform Widal test (Remel, BioSystems, Dialab and Biotec). (ii) Compare the sensitivity and specificity of both anti-O and anti-H antibodies. (iii) Compare the validity of single versus paired serum samples with a rising titer for the diagnosis of typhoid fever. METHODS: Duplicate serum samples were obtained from 150 patients clinically diagnosed as typhoid fever patients. Moreover, single serum samples were obtained from 25 patients with febrile diseases other than typhoid fever. All samples were tested using the four different Widal brands and Salmonella Typhi IgM anti-LPS ELISA. RESULTS: -The results of Widal tests differed markedly using the four Widal brands in terms of sensitivity and specificity at three cut-off values of 1/80, 1/160 and 1/320. Remel brand gave the highest sensitivities and the lowest specificities and Dialab brand gave the highest specificities and the lowest sensitivities for both anti-O and anti-H antibodies at the three cut-off values.-Four fold rise in the antibodies titer was not demonstrable among clinically diagnosed typhoid fever patients-H agglutinins were less sensitive and less specific than O agglutinins CONCLUSIONS: -Widal test results showed marked discrepancies using different Widal brands. None of the serum samples of the typhoid fever patients showed four fold rise in the antibody titers. Raised O agglutinins were of slightly greater diagnostic value than raised H agglutinins. SIGNIFICANCE AND IMPACT OF STUDY: Widal test done sequentially using two brands could be of value in typhoid fever diagnosis. Single serum sample could be used for typhoid fever diagnosis relying on anti O titer.
Subject(s)
Serologic Tests/methods , Typhoid Fever/diagnosis , Adolescent , Adult , Aged , Antibodies, Bacterial/blood , Antigens, Bacterial/analysis , Antigens, Bacterial/immunology , Child , Child, Preschool , Female , Humans , Male , Middle Aged , Reagent Kits, Diagnostic , Salmonella typhi/immunology , Salmonella typhi/isolation & purification , Serologic Tests/instrumentation , Typhoid Fever/immunology , Typhoid Fever/microbiology , Young AdultABSTRACT
BACKGROUND: The value of the Widal test for the diagnosis of typhoid fever has been debated for as many years as it has been available. TUBEX test is a serological test which was stated to have the advantages of the Widal test without its controversies. The aim of this study was to evaluate TUBEX test versus the Widal test regarding sensitivity and specificity for the diagnosis of typhoid fever in an endemic area like Kafr El -Shekh, Egypt. MATERIALS AND METHODS: Serum samples were collected from typhoid (n=91) and febrile non-typhoid patients (n=25) and used to evaluate the performance of both Widal and TUBEX tests in diagnosis of typhoid fever using IgM anti-LPS ELISA as a reference test. RESULTS: TUBEX test had sensitivity, specificity, accuracy, positive predictive value and negative predictive value of 74.6%, 75%, 74.7%, 89.2% and 58% respectively. Widal test had higher results. CONCLUSION AND RECOMMENDATION: TUBEX test results are not superior to Widal test. TUBEX has a very serious shortcoming regarding its color scoring system. We do not recommend the use of TUBEX test for diagnosis of typhoid fever in Egypt as Widal test which is the test commonly used in diagnosis gave better performance.
