MS JOSEPHINE NYABETA RIOKI

Background: Tuberculosis is a major public health problem in Kenya as well as other developing countries. Diagnosis of extra-pulmonary tuberculosis is a common challenge especially where direct Ziehl Neelsen (ZN) technique is employed.
Objective: This study was aimed to establish whether modification of ZN by use of 3.5% NaOCl-Xylene Floatation would improve the detection of acid-alcohol fast bacilli (AAFBs) from lymph node aspirates.
Design: This was a descriptive cross-sectional study.
Setting: Kenyatta National Hospital, Kenya.
Subjects: One hundred cases suspected of clinically having TB with lymphadenopathy referred for fine needle aspiration cytology (FNAC) in FNA Clinic at Kenyatta National Hospital.
Methodology: The study was approved by Kenyatta National Hospital/ University of Nairobi/ Ethics and Research Committee (KNH/UON/ERC) and informed consent sought from patients. Analysis was done using SPSS version 12.0 for Windows (SPSS Inc.). McNemar’s test was used to assess the level of significance for the two test procedures. Chi-square was used to assess for the heterogeneity of the association between the two study methods.
Results: Thirty (30%) of the specimens were positive with fluorescent microscopy, 17% were modified ZN positive while 6% were direct ZN positive. The sensitivity, specificity, positive and negative predictive values for the modified technique (3.5% NaOCl-Xylene Floatation) were 53.3%, 98.6%, 94.1%, and 83.1% respectively.
Conclusions: Liquefaction of the aspirated specimens with NaOCl followed by Xylene floatation significantly increased the yield of AAFBs. This finding is of great interest in developing countries where smear-negative for acid-alcohol fast bacilli (AAFBs) has become common.
Recommendation: Local settings should consider adopting use of modified ZN technique in order to increase the sensitivity and detection rate of AAFBs from lymph node aspirates.

Background: Cryptococcal meningitis is a fatal opportunistic infection in immune-compromised patients. Lack of simple, affordable, rapid and specific methods for diagnosis in many government health facilities in Kenya has aggravated patients’ conditions.
Objective: This study was aimed at determining the performance of India ink (Microscopy), latex agglutination test (LAT) and enzyme immunoassay (EIA) in the diagnosis of cryptococcal meningitis in a Kenyan population.
Design: Laboratory based cross-sectional study.
Setting: A high-volume government health facility based in Nairobi.
Subjects: One hundred and thirteen CSF samples from HIV positive patients with signs and symptoms of cryptococcal meningitis sent to the laboratory for routine analysis.
Methodology: The study was approved by the KEMRI Scientific Committee/Ethics Review Committee and informed consent sought from the patients. The test for the agreement between the test methods and the gold standard (Culture) was calculated using the non-parametric McNemar’s test using SPSS version 17 (SPSS Inc., Chicago, IL) at 5% significant level.
Results: Twenty one point six percent of all samples tested positive on LAT while 9% were positive on microscopy, EIA and culture. The sensitivity, specificity, positive and negative predictive values for microscopy and EIA were: 90%, 99%, 90% and 99% respectively. By LAT, the values were: 100%, 86.1%, 41.7% and 100% respectively. Both EIA and microscopy had an agreement of 89% whereas that of LAT was 52.8% with the gold standard (C.S.F culture).
Conclusion: From the results of this study, it is evident that Latex Agglutination Test was the most sensitive among the study methods. Therefore, LAT is an appropriate diagnostic test but requires confirmatory testing. EIA could be an appropriate confirmatory test but is limited because it is not available in our setup. India ink though available is user-dependent, a major limitation. The use of test combinations did not increase the sensitivity of neither India ink nor enzyme immunoassay and is therefore not significant in the diagnostic work up for cryptococcal meningitis.
Recommendations: Local settings may consider frequent and unlimited use of LAT as a sensitive diagnostic tool for cryptococcal meningitis. It is also important to note that positive LAT tests are accompanied with a confirmatory test due to unfavourable specificities as evidenced from the research findings. In areas where cost is not a limitation, EIA may be used as a confirmatory test. Future research of comparing lateral flow immunoassay (LFA) and the current test methods using CSF in our hospital set up is warranted.