Blood tests:
↑ Hematocrit and hemoglobin (hemoconcentration)
↑ Serum sodium (hypernatremia in some cases)
↑ Blood urea nitrogen (BUN) and creatinine
↑ Serum osmolality
Urine tests:
↑ Urine specific gravity (>1.020)
↓ Urine sodium
Blood Urea/Creatinine Ratio is considered to be an ideal biomarker of dehydration.