Validity of serum Adenosine deaminase in diagnosis of tuberculosis

Abstract

IntroductionTuberculosis is one of the most important infectious causes of death worldwide. Ziehl-Neelsen staining of sputum has high specificity in tuberculosis endemic countries, but modest sensitivity which varies among laboratories. This study was set up to investigate the diagnostic value of serum Adenosine deaminase in diagnosis of tuberculosis.MethodsIn a cross sectional and prospective study Serums of 200 patients of positive sputum smear, negative sputum smear, extra-pulmonary tuberculosis and bacterial community acquired pneumonia collected from March 2011 to May 2012 were evaluated. The data were analyzed using SPSS software and P-value of <0.05 was considered significant.ResultsA total of 200 subjects were included in the study designed in four groups. In cut-off value of ≥24 U/l for ADA in smear positive patients defined the sensitivity, specificity and positive predictive value 12%, 98% and 86% respectively. In smear negative patients defined the 6%, 98% and 75%, and in extra-pulmonary tuberculosis patients defined the sensitivity 14%, 98% and 88% respectively.ConclusionThis study indicated that measurement of serum ADA level do not have enough sensitivity to assist in the diagnoses of tuberculosis patients from other respiratory diseases and not evaluated perform well enough to replace sputum smear microscopy. Thus, this tests have little role in the diagnosis of pulmonary tuberculosis.

Utility of serum ADA estimation in the diagnosis of extrapulmonary tuberculosis

“…11,12 However, this observation is in contrast with the study by Aliasgarh Farazi that showed low sensitivity of serum ADA assay for differentiating TB from other respiratory illnesses and thus disapproved its utility for TB diagnosis. 13 The finding of higher activity in EPTB than PTB patients in the present study could be due to the higher T lymphocytes activity in that group. However, since in EPTB group, tubercular foci may not be proximal to the bronchial tract, sputum smear examination is negative.…”

Diagnostic Value of Serum Adenosine Deaminase (ADA) Level for Pulmonary Tuberculosis

“…Although tuberculosis (TB) is a known infectious disease with a definite epidemiological pattern and known principles of treatment since 60 years ago, yet there is still a considerable number of TB patients in many parts of the world including our country, who are not timely diagnosed and properly treated ( 1 , 2 ). Tuberculosis remains to be a major health problem in many parts of the world including Iran ( 3 ).…”

“…Each year, about nine million active TB cases occur and 1.5 to 2 million people die of this disease worldwide ( 2 ). Although the standard method for TB diagnosis is direct observation of acid-fast bacilli in sputum smear or M. tuberculosis isolation in specific culture media ( 1 - 3 ), yet this method is not always easy to perform. Therefore, employing other methods with shorter duration and acceptable sensitivity and specificity is necessary to diagnose TB in special situations ( 4 ).…”

“…Although PCR is the most sensitive and rapid method for diagnosis of TB, yet due to its high costs, it is not available in limited resource areas ( 5 ). For this purpose, activity of adenosine deaminase (ADA) enzyme in serum and body fluids, such as sputum, pleural effusion, ascites and cerebrospinal fluid has been taken into consideration ( 1 , 6 , 7 ). The ADA is an enzyme (EC 3.5.4.4) that is involved in the metabolism of purine and catalyzes the hydrolytic deamination of adenosine to inosine, and deoxyadenosine to deoxyinosine.…”

“…The ADA is an enzyme (EC 3.5.4.4) that is involved in the metabolism of purine and catalyzes the hydrolytic deamination of adenosine to inosine, and deoxyadenosine to deoxyinosine. This enzyme plays an important physiological role in regulation of the effects of these metabolites on immunological, neurological and vascular processes ( 1 , 6 - 8 ). The ADA plays an important role in proliferation and differentiation of lymphocytes, particularly T lymphocytes ( 9 ).…”