| Guideline Organization/Society |  | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Criteria/Categories | NIV [16] | NHS [17] | GAIN [22] | AEEH [23] | EHN [25] | ERBP/ESE/ESICM [20] | UF [18] | HEP [19] | RCHM [21] | EAH-ICD [24] |
Threshold workup [Na] | <135Â mmol/L | <135Â mmol/L | <135Â mmol/L | <130Â mmol/L | <135Â mmol/L | <135Â mmol/L | <131Â mmol/L | <135Â mmol/L | <135Â mmol/L | Â |
Confirming hypotonic hyponatremia | Serum osmolality <275Â mOsm/kg | Plasma osmolality <280Â mOsm/kg | Serum osmolality <275Â mOsm/kg | Â | Plasma osmolality <275Â mOsm/kg | Serum osmolality <275Â mOsm/kg | Serum osmolality <285Â mOsm/kg | Plasma osmolality <280Â mOsm/kg | Serum osmolality threshold not stated | Â |
How to classify hypotonic hyponatremia to aid identification of underlying cause | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Volume status/hydration state/extracellular fluid status | Clinical evaluation | Physical examination/clinical signs of dehydration or edema | Physical examination/clinical signs of dehydration or edema | Â | Physical examination/clinical signs of low circulating volume | Physical examination/clinical signs of dehydration or edema | Physical examination/laboratory measurements | Physical examination/laboratory measurements | To assess but method not stated | Â |
Urinary [Na]/Threshold | 30 mmol/L | Spot urine: 20–30 mmol/L | 15 mmol/L |  | 40 mmol/L | 30 mmol/L | 25 mmol/L | Spot urine: 20–30 mmol/L | No threshold stated |  |
Urinary osmolality/Threshold | 100Â mOsm/kg | 100Â mOsm/kg | 100Â mOsm/kg | Â | 100Â mOsm/kg | 100Â mOsm/kg | 100Â mOsm/kg | 100Â mOsm/kg | No threshold stated | Â |
How to identify the underlying disorder | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
History | Â | Medications | Medications | Â | Â | Diuretic use | Â | Â | Â | Â |
 |  | Fluid intake | Recently prescribed intravenous fluids |  |  |  |  |  |  |  |
 |  | Nocturnal polyuria | Vomiting/diarrhea |  |  |  |  |  |  |  |
Lab tests | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Serum potassium concentration | + | + | Â | Â | Â | Â | Â | Â | + | Â |
Serum chloride concentration | Â | + | Â | Â | Â | Â | Â | Â | + | Â |
Serum urea concentration | +/– | + |  |  |  |  | +/– | +/– | + |  |
Serum creatinine concentration | + | + |  |  |  |  | +/– | +/– | + |  |
Serum glucose concentration | + | + | +/– |  |  | + |  |  | + |  |
Urinary potassium concentration | + | Â | Â | Â | Â | Â | + | Â | Â | Â |
Renal tests | Â | Â | + | Â | Â | Â | Â | Â | Â | Â |
Liver tests |  |  | + |  |  |  | +/– |  |  |  |
Urinary protein |  | +/– |  |  |  |  |  |  |  |  |
Thyroid function tests | +/– | +/– | +/– |  |  |  | +/– |  |  |  |
Adrenal function tests | +/– | +/– | +/– |  |  |  | +/– |  |  |  |
Serum protein electrophoresis |  | +/– |  |  |  |  |  |  |  |  |
Urine protein electrophoresis |  | +/– |  |  |  |  |  |  |  |  |
Fractional sodium excretion | +/– |  |  |  |  |  |  |  |  |  |
Serum uric acid concentration | +/– | +/– |  |  |  |  | + | +/– |  |  |
Fractional uric acid concentration | +/– |  |  |  |  |  |  |  |  |  |
Fractional excretion urea | +/– |  |  |  |  |  |  |  |  |  |
Urinary chloride concentration | +/– |  |  |  |  |  | + | +/– |  |  |
Molar weight urine | +/– |  |  |  |  |  |  |  |  |  |
Serum bicarbonate concentration |  |  |  |  |  |  | +/– |  |  |  |
Hematocrit |  |  |  |  |  |  | +/– |  |  |  |