Clinical meaning
Laboratory diagnostics provide objective data that complement clinical assessment findings. Blood samples undergo centrifugation to separate cellular components from plasma, enabling analysis of individual analytes such as electrolytes, glucose, and blood cell counts. The complete blood count (CBC) evaluates red blood cells, white blood cells, and platelets, reflecting oxygen-carrying capacity, immune function, and clotting ability respectively. The basic metabolic panel (BMP) assesses kidney function, electrolyte balance, and glucose metabolism, forming the cornerstone of routine diagnostic evaluation in most clinical settings.
Exam relevance
Risk factors: - Hemolyzed specimens leading to falsely elevated potassium - Improper specimen labeling causing patient identification errors - Prolonged tourniquet application altering electrolyte values - Drawing blood from an IV arm producing diluted or contaminated results - Delayed specimen transport affecting glucose and coagulation results
Diagnostics: - CBC: WBC 4,500-11,000/mcL, RBC 4.5-5.5 million/mcL (male), Hgb 12-16 g/dL (female) 14-18 g/dL (male), Hct 36-46% (female) 40-54% (male), Platelets 150,000-400,000/mcL - BMP: Sodium 135-145 mEq/L, Potassium 3.5-5.0 mEq/L, Chloride 96-106 mEq/L, CO2 22-28 mEq/L, BUN 7-20 mg/dL, Creatinine 0.6-1.2 mg/dL, Glucose 70-100 mg/dL fasting - Urinalysis: pH 4.5-8.0, specific gravity 1.005-1.030, negative for protein, glucose, blood, nitrites, and leukocyte esterase - Basic coagulation: PT 11-13.5 seconds, INR 0.8-1.1 (therapeutic 2.0-3.0), PTT 25-35 seconds