Diagnosis and Classification of Leprosy Patients in Sudan using Lateral Flow assay for Phenolic Lipoglycolipid-1 Antibody
Background Leprosy diagnosis is a clinical issue since the culture of the causative organism M. Lepra is impossible. Variations in the clinical picture of the disease render the supportive lab investigations very important in establishing the correct diagnosis and classification of the patients into Mutibacillary (MB) and Paucibacillary (PB). Since the treatment options relay on the proper classification into MB or PB, the availability of a robust and practical test which can aid in this undertaking is of utmost importance. A study of the usefulness of the ML flow test in the diagnosis and classification of leprosy patients in Sudan is presented here.
Research methods Sixty leprosy patients diagnosed clinically in Khartoum Dermatology & Venereology Hospital were recruited to undertake the ML flow test; another 10 healthy individuals and 10 patients with various dermatological diseases were tested as well. The results were compared with the current method of classification employed by the leprosy clinic staff in the hospital i.e. WHO lesion count classification. The agreement between the two methods was analyzed using Kappa coefficient. Clinical data was gathered as well.
Results According to the ML flow test, 45 patients were positive (MB) while 15 patients were negative (PB). The WHO classification identified 43 MB patients and 17 PB patients. Three patients were classified as MB according to the WHO criteria turned out to be PB by the ML flow test while five patients were classified as PB according to the WHO criteria turned out to be MB by the ML flow test. The agreement between the two methods was measured using Kappa coefficient, which scored 0.67; this is considered to be substantial agreement according to Landis and Koch’s guideline. None of the control group was positive by the test.
Conclusions The ML flow test showed good concordance with the WHO criteria, but a clinically significant portion of the patients may benefit from the ML flow test in the classification process. It is a useful and practical tool in the diagnosis and classification of leprosy patients in Sudan.