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Conclusion
Conflicts of interest
Compliance with ethical standards
Introduction
Tuberculosis is one of the leading causes of morbidity and mortality, amongst infectious diseases. India is a high burden country for Tuberculosis. Caused by Mycobacterium tuberculosis, it Exendin-3 (9-39) amide can present as pulmonary tuberculosis (PTB) or extra-pulmonary tuberculosis (EPTB). Sputum smear microscopy is routinely used for diagnosis of PTB. Despite best of the efforts, a clinician may have to face difficulties in smear negative patients, and sometimes, it becomes almost impossible to diagnose this entity. The presence of co-morbidities like diabetes mellitus, HIV and other immune compromised conditions further complicate the picture as they lead to atypical clinical and radiological presentations.3, 4 This delay in diagnosis and subsequent treatment leads to increased disease transmission and chances of drug resistance. Hence, in the recent years, there has been a great demand for finding a rapid diagnostic method for the same.
Adenosine deaminase (ADA) is one such biomarker which is now a days being studied as a diagnostic tool in tuberculosis.6, 7, 8 Literature is available on its role in effusion fluids. However, limited literature is available regarding the use of serum ADA in active disease, and whether the levels fall with the recovery of the patients from infection.6, 7, 8, 10, 11, 12
Material and methods
The patients and controls were grouped as follows:
EPTB, old treated cases of PTB, patients<18 years of age and patients with other respiratory diseases were excluded.
All subjects undergoing the study were given necessary information and informed consent was taken on a standard proforma. Detailed history was taken from each subject and a thorough clinical examination was done. Investigations as per the requirement, varying from case to case, were carried out for the diagnosis of tuberculosis. In addition blood sample was collected from a vein in the ante-cubital fossa after the surface was sterilized with spirit. 5ml of blood was collected in a disposable syringe under strict aseptic conditions. The blood thus collected was centrifuged immediately and serum separated. ADA levels were measured (Diazyme ADA assay kit; by enzymatic photometric method) on Hitachi 902, Random Access Chemistry Analyser on the same day, or else the serum samples were stored at −20°C. Serum ADA levels were measured at baseline in all the 3 groups, and repeated in patients of PTB (sputum positive and sputum negative) at the end of IP of treatment.
Statistical analysis
All collected data was entered in the Microsoft excel spread sheet. Data was expressed as mean±SD or median and inter-quartile range as appropriate for the parametric data and means were compared using paired T-test. P value of ≤0.05 was taken as statistically significant. All analysis was done in SPSS trial version 17 (statistical package for Social Sciences). Kolmogorov–Smirnov tests of normality were used to know normality of quantitative data. For skewed data, Mann–Whitney U test and Kruskal–Wallis test were used to assess differences between nonparametric data and Post Hoc test was done for pair wise comparison. Wilcoxon Signed Rank test was used to compare data at different points of time. Correlation analysis was done using Spearman's Rank test for skewed data and Pearson Chi-square test for normally distributed data.
Results
The 3 groups were matched for age and gender. The mean age of the patients was found to be 37.20±15.29, 36.08 and 32.48±9.381 years in the groups A, B and C respectively.
The co-morbidities in Group A and Group B are mesoderm shown in Table 1.
Mean serum ADA was found to be 35.293±30.941IU/L in PTB patients and 11.819±8.023IU/L in control groups. The difference in the mean values was found to be highly significant statistically (P<0.00).
Mean serum ADA was found to be 31.107±29.32IU/L in sputum positive PTB, 39.478±32.22IU/L in sputum negative PTB and 11.819±8.0235IU/L in control groups (Fig. 1).