Table 3: Hyponatremia-directed study.

Parameter

Result

Reference Value

Plasma osmolarity

272

285 - 295 mOsm/dL

Urine osmolarity

141

100 mOsm/kg

Plasma Sodium

107

136 - 145 mmol/L

Plasma Potassium

4.9

3.6 - 5.0 mmol/L

Urinary Sodium Fractional excretion ratio

<1%

<1%

Plasma Chloride

83

98 - 107 mmol/L

TSH

1.36

0.4 - 4.0mU/L