Background There has been no in-depth study examining the preanalytical direct immunofluorescence (DIF) biopsy phase for patients with cicatricial conjunctivitis.

Methods 90 patients with cicatricial conjunctivitis had biopsies taken for DIF. The study examined the following biopsy and clinical parameters: Age and sex of patient, unilateral or bilateral involvement, unilateral or bilateral biopsy, site of biopsy, nature of biopsy site (normal or diseased), number of biopsies per eye, size of biopsy, medium in which biopsy sent, whether buccal mucosa biopsied, whether tissue biopsied for histology (fixed in formalin) DIF results for conjunctival and buccal biopsies and final clinicopathological diagnosis.

Results Most cases had unilateral sampling despite many cases showing bilateral disease. 15/90 cases had buccal biopsies. The conjunctival site for biopsy was not consistent from case to case. The mean maximum biopsy size was 3.3 mm length, 1 mm depth. No case was inadequate for DIF. Biopsies were obtained from conjunctiva with varying disease activity. 80/90 cases were sent in an appropriate medium permitting DIF. DIF+ biopsy rates were not affected by biopsy site disease activity. Five cases of bilateral involvement and bilateral biopsies showed only unilateral DIF+. In five cases, the conjunctival biopsies were DIF+ and the buccal biopsy was DIF−. Five cases showed in situ and invasive carcinoma seen on the accompanying formalin-fixed biopsy.

Conclusions DIF biopsies for cicatricial conjunctivitis showed highly variable preanalytical phase sampling practice that requires national and international standardisation to facilitate prompt diagnosis, treatment, research and audit.