Measurement of small tissue volumes using Holden's apparatus.

A reproducible method for the estimation of volumes of small tissue samples was needed to allow comparison of the biological activity of tissue explants and to relate symptom improvement to procedures such as adenoidectomy or polypectomy. Holden's apparatus, which utilizes fluid displacement between two chambers, was compared to displacement in a 20 ml syringe. Two observers made four readings each on 20 tissue samples (range 0.37 to 4.70 ml) using both methods for comparison. A two-way analysis of variance for replicated data gave an F ratio of 0.6885 (df = 19; p > 0.8) for Holden's apparatus, and an F ratio of 1.4307 (df = 19; p > 0.1) for the 20 ml syringe. The standard error of the mean for repeated readings on the same sample by an observer was 0.001 ml for Holden's apparatus and 0.014 ml for the syringe method. For accurate estimation of small tissue volumes within 0.01 ml we recommend Holden's apparatus.