Leprosy Mailing List – March 11, 2013
Ref.: (LML) Bacillary Index
From: Andrea Clapasson, Genova, Italy
Dear Dr. Schreuder,
I would like to thank Professor Nora Cardona Castro for her message dated LML 11 March 2013. She commented that the interpretation of the scale for the calculation of the bacteriological index (BI) reported by WHO [may generate some confusion and specifically you asked three questions.
Herewith are my answers to the important aspects that you have pointed out.
1) Is the nasal swab included [do we need using the logarithmic scale for reading and reporting the nasal swab]?
I don't use the logarithmic scale (BI) when I read the nasal swabs. I report only a description about the morphology of the bacilli and if globi are present. Nasal swab positive for "solids" [solid-staining M. leprae] indicates the infectiousness of the patient. Nasal swab is not used for diagnosis or classification.
2) Is the BI the average of the numbers of "+" found in all the fields?
Yes, it is. Please find herewith in attachment an PDF file with an example of the report form used in our hospital. It refers to a patient whose last BI was 2.83+ and MI 0.3%
3) Is the BI chosen according the most high "+" in any site?
No, as previously said it is the average of the results at the different sites. The BI gives an indication of the total bacterial load of patient. However, I record the value of each site for better monitor the response to therapy in different parts of the body.
Dr. Andrea Clapasson
National Leprosy Referral Centre,
Unit of Social Dermatology,
''San Martino'' University Hospital - IRCCS,
LML - S Deepak, B Naafs, S Noto and P Schreuder
LML Archives: temporary not available, until further notice.
Contact: Dr Pieter Schreuder << firstname.lastname@example.org >>.