Modified Widal test using 2-mercaptoethanol for detecting anti-salmonella IgM in febrile patients Agarwal R. K.1, Chatterjee B.2,*, Mittal G.3, Bhatla T.4, Agarwal Ankit5 1Professor, Dept. of Microbiology, Himalayan Institute of Medical Sciences, Dehradun, Uttarakhand 2Associate Professor, Dept. of Microbiology, Himalayan Institute of Medical Sciences, Dehradun, Uttarakhand 3Associate Professor, Dept. of Microbiology, Himalayan Institute of Medical Sciences, Dehradun, Uttarakhand 4MBBS Intern, Dept. of Microbiology, Himalayan Institute of Medical Sciences, Dehradun, Uttarakhand 5Associate Professor, Dept. of Anesthesiology, All-India Institute of Medical Sciences, Rishikesh, Uttarakhand, India *Corresponding Author: Email: doctorbiswaroopchatterjee@gmail.com
Online published on 14 January, 2019. Abstract Introduction Despite limitations, the Widal test is widely used in resource-constrained settings because it is fast, inexpensive and user-friendly. Therefore, efforts continue to improve its diagnostic utility. Aims Using 2-mercaptoethanol (2-ME) to detect the IgM fraction of total agglutinins detected by the Widal test in the serum of febrile patients. Materials and Methods Single serum specimens were collected from 333 patients presenting to our hospital with fever. One aliquot of serum was tested by standard Widal test; a positive result was defined as simultaneous elevation of ‘O’ and ‘H ’titres to 1: 80 or above. A second aliquot was simultaneously tested by a modified Widal test in which serum was diluted in isotonic saline with added 2-ME (0.12M) instead of in plain isotonic saline. Differences in titre between the two versions of Widal test were noted. A four-fold or greater reduction in titre upon testing with 2-ME, was considered evidence of specific IgM. Results Standard Widal test was positive in 55 (16.5%) out of 333 patients. A ≥4-fold reduction of ‘O’ titre in modified Widal test was found in 38 (69.1%) out of 55 cases, indicating the presence of specific IgM. A similar reduction of ‘H ’titre was seen in only 6 (11%) out of 55 cases. Conclusion Simultaneous use of standard Widal test and modified Widal test with 2-ME allows the detection of specific IgM at a low cost. This can increase the diagnostic utility of the Widal test. Top Keywords Acute febrile illness, Typhoid fever, Serology, IgM, Laboratory diagnosis. Top |