BackgroundFor the calculation of parasite index (PI) by microscopy method, an assumed total leucocyte count (TLC) of 8,000/μL is used conventionally. However, due to obvious variation in the population and individual TLCs, use of 8,000/μL may result in either over/underestimation of the PI.MethodsThis study was aimed at ascertaining the utility of 8,000/μL TLC, as well as other assumed TLCs, with respect to measured TLC for the calculation of PI. A tertiary care hospital and five primary health centres were the base for the prospective study conducted among microscopically proven, symptomatic Plasmodium vivax mono-infection patients aged ≥18 years. PIs calculated by assumed TLCs ranging from 4,000-11,000/μL were compared with those calculated by measured TLCs. Geometric mean with 95% confidence interval, Bland-Altman plot and Wilcoxon signed rank test were used for statistical analysis.ResultsA total of 284 P. vivax mono-infection patients, including 156 from a tertiary care hospital and 128 from five primary health centres, were recruited in the study. Assumed TLCs below 5,000 cell/μL and above 5,500 cell/μL in tertiary care setting resulted in significant (p <0.05) underestimation and overestimation, respectively. However, in primary health centres, it was an assumed TLC of 5,000 cell/μL, below and above which there was significant (p <0.05) underestimation and overestimation observed, respectively.ConclusionsAssumed TLC of 8,000/μL is not suitable for the calculation of PI. Either actual TLC of the patient should be measured or a representative TLC should be derived for the population under investigation for any study requiring calculated PI by microscopy.

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Background: The interface between tuberculosis (TB) and Crohn’s disease (CD) is relevant as TB complicates both the diagnosis and management of CD. Aim: This study aimed to identify the distinctive characteristics of ileocaecal and colonic TB (C‑TB) and colonic CD (C‑CD) at colonoscopy and to correlate the colonoscopy findings with histology. Materials and Methods: This prospective study included consecutive patients presenting with classical symptoms of TB or CD. The colonoscopic findings were compared with histology, which was taken as gold standard. Appropriate statistical tests were applied. Results: Fifty‑eight individuals fulfilled the inclusion criteria. Nine and 16 patients with C‑TB and C‑CD, respectively, had histological confirmation of respective diagnosis. In 33 specimens, the histological diagnosis was inconclusive. The sensitivity of colonoscopy for diagnosing C‑TB was high at 88.9% (95% confidence interval [CI]: 51.8–99.7). It was 50% (95% CI: 24.7–75.4) for CD. The reverse was true for CD whose specificity was high at 71.4% (95% CI: 55.3–84.3) and low for TB at 46.9% (95% CI: 32.5–61.7). All the patients diagnosed as confirmed CD or TB responded well to respective treatment. Six of the thirty patients with failed response to anti‑TB treatment required surgery or change in treatment after 2 months. Conclusion: Colonoscopic findings of isolated ileal involvement, aphthous ulcer, cobble stoning, long‑segment strictures, skip lesions and perianal involvement favored a diagnosis of CD. Correlation of colonoscopy with histology is poor for both CD and TB. The accuracy, sensitivity and specificity of colonoscopy were better and superior for the diagnosis of CD, than in the diagnosis of TB.

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