Noninstrumented enzyme-linked immunosorbant assay for detection of early pregnancy in macaques

A practical, noninstrumented enzyme-linked immunosorbant assay (NELISA) for the measurement of urinary monkey chorionic gonadotropin (mCG) has been de veloped for the detection of early pregnancy in macaque monkeys for use in both the laboratory and the field. Five rhesus monkeys (Macaca mulatta) and six crab-eating monkeys (Macaca fascicularis) were tested for the presence of mCG in urine on gestational days (GDs) 12 to 35. The mCG NELISA detecte d pregnancy as early as GD 14, with an average earliest detection at GD 16. 5 +/- 1.4 (n = 11), Out of 90 tests, 27 false-negative and zero false-posit ive tests were obtained, for an accuracy of 70.0%. Without the aid of a spe ctrophotometer, the presence of mCG in pregnant monkey samples was indicate d by a dark green color change. Nonpregnant monkey urine samples, on the ot her hand, exhibited no color change. These findings suggest that the simple , economical, and reliable urinary mCG NELISA may be useful for diagnosing early pregnancy in these and related species. Because capture and restraint are unnecessary for collecting urine samples, the mCG NELISA has widesprea d potential for confined and free-ranging animals. (C) 2001 Wiley-Liss, Inc .