Describe the general approach.
Diagnosing dehydration and/or hypovolemia relies on clinical assessment
Laboratory studies can help support the clinical diagnosis but are not routinely required.
Obtain laboratory studies for:
Severe fluid loss requiring IV fluids
Moderate fluid loss following unsuccessful enteral (e.g., PO/NG) fluid replacement
Evaluation of the underlying cause, e.g., diabetes insipidus, hyperglycemic crises
Which laboratory studies should be ordered?
Orders: to evaluate severe fluid loss
BMP: Serum Na used to guide treatment.
CBC
Lactate
Uric acid
POC glucose
Urinalysis
Urine electrolytes: e.g., urine Na
What are the possible laboratory findings?
Interpret in context on an individual basis
Vary depending on:
Predominance of dehydration vs. hypovolemia
Age: e.g., infants, older adults
Underlying etiology: e.g., diabetes insipidus
Medications: e.g., diuretic use
Comorbidities: e.g., CKD
Lab findings in dehydration/hypovolemia (table).
Last changed2 years ago
