of prescribed medication, diuretic use or antidepressant
medication was similar in those considered by nurses to be
dehydrated or hydrated. Patients who were dehydrated had a
significantly higher admission median blood sodium (142 vs.
138 mmol/L), U:C ratio (105 vs. 62 mmol:mmol), and median
plasma osmolality (308 vs. 298 mOsm/kg) than those who
were not dehydrated (all P < 0Æ05, Mann–Whitney U-tests)
(Table 1). Dehydrated patients also had a higher median test
strip USG (1Æ020 vs. 1Æ010 SG units) and refractometer USG
(1Æ022 vs. 1Æ014 SG units) and Ucol (6 vs. 5) than those
hydrated, but these differences were not statistically significant
(all P > 0Æ05, Mann–Whitney U-test) (Table 1). Overall the
within-subject agreement between the refractometer USG
being >1Æ020 SG units (indicator of dehydration) and nurses
opinion that patients were dehydrated on admission was 84%
(95% confidence intervals, CI, 60%, 97%).