What lab tests indicate hypovolemia?

As a medical professional with expertise in clinical diagnostics, I can provide insight into the lab tests that may indicate hypovolemia. Hypovolemia refers to a decrease in the volume of blood or other body fluids, which can lead to various physiological imbalances. Here are some key lab tests that can be indicative of hypovolemia: 1. CBC (Complete Blood Count): A low hematocrit (HCT) may suggest a loss of plasma, which can be a sign of hypovolemia. 2. Electrolyte Levels: Abnormalities in sodium (Na), potassium (K), chloride (Cl), and bicarbonate (HCO3) can suggest dehydration or fluid imbalances. 3. BUN (Blood Urea Nitrogen) and Creatinine: Elevated levels can indicate decreased renal perfusion due to hypovolemia. 4. Glucose Levels: Hypoglycemia could be a sign of shock or stress response in the body. 5. Lactate: Increased levels can be a marker of tissue hypoxia, which may result from hypovolemia. 6. Prothrombin Time (PT) and **Activated Partial Thromboplastin Time (aPTT)**: Prolonged times can suggest a coagulopathy that may accompany severe hypovolemia. 7. ABGs (Arterial Blood Gases): These can show metabolic acidosis or other imbalances due to hypovolemia. 8. Urinalysis: In patients with trauma, this can help identify myoglobinuria, which can be associated with rhabdomyolysis and hypovolemia. 9. Urine Pregnancy Test: In women of childbearing age, this can be important to rule out pregnancy-related issues that could mimic hypovolemia. It's important to note that while these tests can provide valuable information, the diagnosis of hypovolemia is typically made through a combination of clinical assessment, patient history, and these lab findings.

Initial laboratory studies should include analysis of the CBC, electrolyte levels (eg, Na, K, Cl, HCO3, BUN, creatinine, glucose levels), lactate, prothrombin time, activated partial thromboplastin time, ABGs, urinalysis (in patients with trauma), and a urine pregnancy test. Blood should be typed and cross-matched.