Cost-effectiveness in the diagnosis of sarcoidosis: the conjunctival biopsy.

PURPOSE: Sarcoidosis is a multi-system disease that often affects ocular structures. The definitive diagnosis of sarcoidosis requires tissue biopsy for confirmation. Conjunctival biopsy is a simple and relatively inexpensive diagnostic tool. This study was undertaken to determine the utility and cost of conjunctival biopsy for the diagnosis of sarcoidosis compared with other diagnostic biopsy sites.
METHODS: A retrospective study was performed of all conjunctival biopsies taken for sarcoidosis at the Mayo Clinic Rochester between 1982 and 1995. All case histories were reviewed. Data regarding biopsy of tissues confirming sarcoidosis was collected. The costs of performing and evaluating all biopsy techniques were obtained from the estimating department.
RESULTS: Forty-one cases of sarcoidosis were identified that had undergone conjunctival biopsies. Twenty-one patients had a positive conjunctival biopsy for sarcoidosis, and 20 patients had a negative conjunctival biopsy but a positive biopsy of another organ. In all positive biopsies, special stains for acid fast organisms and fungi were negative.
CONCLUSIONS: Conjunctival biopsy is a simple, relatively inexpensive procedure that may be helpful in establishing the diagnosis of sarcoidosis with a negligible complication rate. Positive results are similar for conjunctival biopsy and mediastinoscopy. About 10 patients can be evaluated with conjunctival biopsy for the cost of one patient undergoing mediastinoscopy. Multiple levels of the tissue must be examined, as distribution of the granulomas may be random. Also, bilateral conjunctival specimens should be obtained to increase the positive yield.