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Clinical Laboratory Review for Toxicology. Objectives. List the common lab tests used in the evaluation of poisoned patients Normal values Describe common calculations based on these tests Interpret the findings of common tests. Basic Metabolic Panel Sodium (135-148) Potassium (3.2-5.0)
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Objectives • List the common lab tests used in the evaluation of poisoned patients • Normal values • Describe common calculations based on these tests • Interpret the findings of common tests
Basic Metabolic Panel Sodium (135-148) Potassium (3.2-5.0) Bicarbonate (22-28) Chloride (95-105) Calcium (8.5-10.5 mg/dl) Other electrolytes Magnesium (1.2-2.0) Phosphorous (2.3-4.3) Electrolytes Units are millieqivilant/L except Ca
Renal function • Creatinine (0.8-1.2 mg/dl) • Blood Urea Nitrogen (8-18 mg/dl)
Liver function • Alananine aminotransferase- ALT SGPT (12-40 IU/L) • Aspartate aminotransferase AST SGOT (12-40 IU/L) • AST and ALT increase with hepatocyte death • Acetaminophen (and most acute toxic causes) produce 10-100 fold elevation while viral/ethanol cause 5-10 fold elevation
Liver function • Alkaline phosphatase (39-117) • Elevation= billiary obstruction • Bilirubin (0.5 to 2.0) • Measures ability of liver to clear toxins • INR (1-1.2) • Measures ability of liver to produce coagulation proteins • Elevation of transaminsase with change in INR= significant liver injury
Blood gas • Shorthand: pH/CO2/O2 • pH 7.35 to 7.42 • <7.3= acidosis • >7.45= alkalosis • Partial pressure of CO2 (38-42 torr) • <36=respiratory alkalosis • >42= respiratory acidosis • Low serum bicarbonate= metabolic acidosis • High serum bicarbonate= metabolic alkalosis
Anion Gap • = Sodium-bicarbonate+ chloride • Normal= 10 to 14 meq/L • Increase anion gap in the setting of metabolic acidosis consider • MUDPILES etc
Osmolar gap • Serum osmolality is measured by the lab • You estimate serum osmolality from other values 2xNa+(Glucose/18)+ (BUN/2.8)+ (EtOH/4.6) • Calculate the difference (“Osmolar Gap”) • Measured-estimated (normal<10) • If the osmolar gap> 10 suspect toxic alcohol