Results of phenol red thread test in clinically normal Syrian hamsters (Mesocricetus auratus).

OBJECTIVE To determine the normal reference range for phenol red thread test (PRTT) values in clinically normal Syrian hamsters (Mesocricetus auratus). ANIMALS Sixteen healthy adult Syrian hamsters (eight males and eight females) were used in this study. PROCEDURE Ophthalmic examinations were performed without chemical restraint. PRTT values were evaluated in both eyes of all Syrian hamsters using a commercial PRTT strip of a single lot number. RESULTS No statistically significant differences between right and left eyes were found for any of the results. The mean ± SD PRTT values for the study population were 6.8 ± 2.5 mm/15 s with a range from 3 to 11.5 mm/15 s. Mean PRTTs in male animals were 5.1 ± 1.2 mm/15 s, whereas mean PRTTs in female hamsters were 8.5 ± 2.3 mm/15 s. Comparison between mean PRTT values in males and females showed a significant difference (P = 0.004). Mean weights for males and females were 80.9 ± 4.8 and 90.6 ± 8.5 g, respectively. No linear relationship between mean PRTT and body weight was found in female (P = 0.46) and male (P = 0.92) hamsters. CONCLUSION This study provides novel data for normal reference ranges of PRTT values in healthy Syrian hamsters. Results of this study may assist veterinarians in the diagnosis of ocular surface disease and syndromes affecting the tear film in these species.