Quantitation of the granuloma fraction in leprosy skin biopsies by planimetry.

The proportion of the dermis occupied by granuloma in histological sections of skin biopsies from leprosy patients is known as the granuloma fraction. It can be estimated by direct microscopy on a scale of tenths using a low-power objective. We have compared this method with measurement of the granuloma fraction by planimetry, which gives comparable results but is much more accurate and precise. The implications of these findings for the objective assessment of the effects of treatment regimes on leprosy are discussed.