Efficacy of Auramine-O Over ZN Stain in Diagnosis of Tubercular Lymphadenitis

BACKGROUND Lymphadenopathy is one of the most common extra-pulmonary manifestation accounting to around 30-40% of Tuberculosis. In high incidence of Tuberculosis globally, it is highly important for a clinician to take a quick decision for the patient in order to identify highly serious tuberculosis positive patient and start therapy. FNAC has become a popular tool in giving a rapid diagnosis. Demonstration of acid-fast organism is a fool proof evidence of tuberculosis as various
cytomorphological picture may differentiate from other disease

OBJECTIVE ‹?ú To analyse the efficacy of Fluorescent stain Auramine-O over Ziehl-Neelsen stain in identifying tubercle bacilli in Lymph node aspirates.

MATERIAL & METHODS A total of 120 patients referred to the Department of Pathology, SNMC & HSK Hospital, Bagalkot for FNAC of palpable lymph node lesion suspicious for tuberculosis were taken for study. FNAC was done using the standard method. Smears from aspirates were subjected to routine cytological stains. Results were categorized into six (6) cytomorphological patterns: (i) Epithelioid Granuloma with Langhansƒ?? giant cells and caseous necrosis. (ii) Numerous  pithelioid cells and granulomas in a reactive background. (iii) Caseous necrosis with few epithelioid cells. (iv) Caseous necrosis with few lymphocytes and histiocytes. No epithelioid cells. (v) Only caseous necrosis without any cell type. (vi) Tubercular abscess showing predominantly neutrophils along with epithelioid cells. ZN stain, Pap stain & Auramine-O fluorescent stains were used to detect acid fast bacilli. A protocol for the examination of the positivity for AFB with a grading system was used.

RESULTS Among 120 cases of tubercular lymphadenitis, most common cytomorphological pattern seen is pattern II & VI. Ziehl-Neelsen stain demonstrated 20.83% (25/120) positive cases whereas Auramine-O stain demonstrated 53.33% (64/120).

CONCLUSION Fluorescent method in combination with cytomorphological pattern of Tubercular lymphadenitis is useful for evaluating lymph node lesions.

The authors declare no conflict of interest.

Not applicable

The datasets used in this study are openly available at [repository link] and the source code is available on GitHub at [GitHub link].