Evaluation of polymerase chain reaction and adenosine deaminase assay for the diagnosis of tuberculous effusions in children.
OBJECTIVE
To evaluate and compare the utility of polymerase chain reaction (PCR) for the diagnosis of tuberculous effusions in children.


METHODS
PCR, adenosine deaminase (ADA) activity and absolute lymphocyte count (ALC) were evaluated in the fluid of 31 tuberculous (20 pleural, 8 ascites and 3 pericardial) and 24 non-tuberculous (10 transudtative ascites, 8 empyema thoracis, 3 malignant pleural and 3 pyopericardium) effusions.


RESULTS
Fluid PCR for Mycobacterium tuberculosis was positive in 74% of tuberculous effusions, whereas it was falsely positive in 13% of the non-tuberculous group. The mean fluid ADA and ALC values were significantly higher in tuberculous effusions than in non-tuberculous effusions (p<0.001). The sensitivity and specificity of PCR, ADA (> or =38 IU/l) and ALC (> or =275/mm3) were 74% and 88%, 81% and 75%, and 90% and 83%, respectively, in diagnosing tuberculous effusions. The sensitivity of PCR, ADA and ALC was 100%, 100% and 88%, respectively, for confirmed tuberculous effusions. When the two tests were combined (either/or positive), the sensitivity increased (90-100%) at the expense of specificity. When both the tests were positive, then the specificity markedly increased (92-96%), but sensitivity of the tests decreased.


CONCLUSIONS
Fluid PCR alone should not be relied on as a single test; rather, combined analysis with either ADA or ALC could be more useful in the diagnosis of tuberculous effusions in children.
Mishra
O P
OP
Department of Pediatrics, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India. opmpedia@yahoo.co.uk
Kumar
R
R
Ali
Z
Z
Prasad
R
R
Nath
G
G
D000243:Adenosine Deaminase / Q000378:metabolism*; D000293:Adolescent; D001201:Ascites / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D004796:Clinical Enzyme Tests / Q000379:methods / Q000592:standards; D016724:Empyema, Pleural / Q000175:diagnosis* / Q000382:microbiology; D005260:Female; D006801:Humans; D007223:Infant; D018655:Lymphocyte Count; D008297:Male; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D010490:Pericardial Effusion / Q000175:diagnosis* / Q000382:microbiology; D010996:Pleural Effusion / Q000175:diagnosis* / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000592:standards; D012680:Sensitivity and Specificity; D014396:Tuberculosis, Pleural / Q000175:diagnosis* / Q000382:microbiology
D000243:Adenosine Deaminase