Immunofiuorescence (IMF) techniques are often of considerable help in the diagnosis of bullous disorders. It must be emphasized however, that they do not circumvent the need for routine skin histopathology. It is by considering the results of IMF and histopathology together that one is likely to avoid making diagnostic errors. As with routine skin histopathology, if the initial IMF findings are negative and the bullous disease is evolving or changing its clinical appearance, both histopathology and IMF tests should be repeated at serial intervals. As with any laboratory or other diagnostic investigation, clinical judgement is at all times paramount in deciding on the correct diagnosis.
Methods
/. Specimens(a) Serum samples. About 10 ml of blood without anticoagulant should be collected and the serum separated from the clotted blood as soon as possible. Such serum samples can be mailed without freezing. Clotted whole blood should never be mailed frozen as this induces massive haemolysis.(b) Skin biopsy specimens. As in diagnostic histopathology the site of biopsy is of crucial importance. In the bullous dermatoses it is preferable to take the erythematous peri-bullous margin of early vesicles or bullae to use for IMF (Fig. t). At the same time it is convenient to excise the whole bulla in an eleptical biopsy so that the bulla and the other edge can be placed in formalin for routine histopathological examination. In general in our experience, punch biopsy