| UKa | urinary kallikrein |
|---|---|
| ULDH | urinary lactate dehydrogenase |
| UMA | ulcerative mutilating acropathy; upright membrane assay; urinary muramidase activity |
| UMI | urinary meconium index |
| UN | ulnar nerve; undernourished; unilateral neglect; urea nitrogen; urinary nitrogen |