U
| U* | Unit |
| U&L, U/L | Upper and lower |
| UA | Urinalysis |
| UC | Uterine contractions |
| UGI | Upper gastrointestinal |
| UGIS | Upper gastrointestinal series |
| ung | ointment |
| UPP | Uvulo Palato Pharyngoplasty |
| URI | Upper Respiratory Infection |
| US | Ultrasound; Ultrasonography |
| UTI | Urinary Tract Infection |
V
| VA | Visual acuity |
| VC | Vital capacity |
| VCUG | Voiding cystourethrography |
| VD | Venereal disease |
| VF | Visual field |
| VSD | Ventricular septal defect |
| VT | Ventricular tachycardia |
| VUR | Vesicoureteral reflux |
W
| WBC, Wbc | White blood cell |
| WD | Well-developed |
| WN | Well-nourished |
| WNL | Within normal limits |
X
| XP, XDP | Xeroderma pigmentosum |
| XT | exotropia |
