Association of serum adenosine deaminase levels in cytologically suggested cases of tubercular lymphadenitis : the experience of a tertiary care Centre

الملخص EN

Background: Tuberculosis (TB), a communicable disease, caused by Mycobacterium tuberculosis requires a simple, rapid test, which can be easily carried out in a laboratory.

Unfortunately, despite a battery of investigations, no definite test is available till date.

Adenosine deaminase (ADA), a biochemical marker has been proposed as a useful surrogate marker for TB as its levels can be measured in body fluids.

Methods: A one-and-a-half-year prospective study of 154 cases presenting with lymphadenitis from January 2019 to June 2020 was undertaken.

Using cytology, lymphadenitis subjects were divided into two groups: Tubercular (104 patients) as a case group and Reactive (50 patients) as a control group.

All cases were followed by serum ADA assay by colorimetric method.

Nonparametric tests were performed to compare the two groups.

Results: The mean age of the participants was 28.99 ± 13.26 years with a F:M ratio of 1.81:1.

Involvement of cervical lymph nodes was most frequent (89.42% cases).

The mean S.ADA level for tubercular and reactive lymphadenitis was 41.71 ± 11.53 U/L and 21.16 ± 4.16 U/L, respectively (P-value < 0.05).

The cut-off value calculated was 32.6 U/L.

The sensitivity, specificity, PPV, NPV, and accuracy were calculated as 79.81%, 100%, 100%, 70.42%, and 86.36%, respectively.

Conclusion: A statistically significant increase was found in serum ADA levels in tubercular lymphadenitis cases compared to reactive lymphadenitis.

Hence, it can be used as an adjunct to FNAC and is a fairly sensitive and specific test.

Since it is difficult to always demonstrate AFB in FNAC smears, ADA can be helpful in establishing a definite diagnosis despite smear negativity.