Direct immunofluorescence (DIF) is a key method for diagnosing bullous diseases and autoimmune conditions, but its detection rate can be influenced by factors like the biopsy site, the number of biopsies, and the instruments used.
A study at the Universidad de Buenos Aires reviewed 136 cases and found that DIF detection rates varied among conditions, with the highest rate in pemphigus vulgaris (100%) and a lower rate in bullous pemphigoid (55.6%).
It was discovered that increasing the number of biopsies improved detection rates, and biopsies taken with a punch had a significantly higher detection rate compared to scalpel biopsies (71.7% vs. 39.1%).