🩸 Lab Tube Color Reference Guide

• Prothrombin Time (PT/INR) - Warfarin monitoring
• Activated Partial Thromboplastin Time (PTT) - Heparin monitoring
• D-dimer - DVT/PE screening
• Fibrinogen levels
• Factor assays (VIII, IX, etc.)
• Anti-Xa levels

• 90% Fill Rule: Underfilled tubes yield falsely prolonged results
• Draw Order: Second tube after blood cultures (prevents contamination)
• Butterfly Sets: May require discard tube to clear air
• Gentle Mixing: 3-4 inversions immediately post-draw

• Therapeutic drug levels (Digoxin, Phenytoin)
• Hormone panels (TSH, Cortisol)
• Immunology markers
• Serology testing
• Tumor markers

• Processing: Allow complete clotting before centrifugation
• Temperature: Room temperature during clotting phase
• Anticoagulants: May extend clotting time significantly
• Hemolysis Risk: Gentle handling during transport essential

• Basic Metabolic Panel (BMP) - Na, K, Cl, CO2, BUN, Creatinine, Glucose
• Comprehensive Metabolic Panel (CMP) - includes liver enzymes
• Lipid profiles - Total cholesterol, HDL, LDL, Triglycerides
• Cardiac markers - Troponin I/T, CK-MB
• Thyroid function - TSH, Free T4

The gel barrier forms during centrifugation, creating a stable separation between serum and cellular components. This allows serum to be aspirated without cellular contamination and maintains specimen integrity for extended periods.

• Immediate mixing: Gentle inversion prevents microclots
• Fill volume: Adequate blood volume ensures proper gel function
• Storage: Serum stable on gel up to 48 hours refrigerated
• Avoid: Vigorous shaking can cause hemolysis

• Arterial Blood Gases (ABGs) - pH, pCO2, pO2
• STAT electrolyte panels
• Ionized calcium
• Ammonia levels (special handling required)
• Emergency chemistry panels

• Sodium Heparin: General chemistry, most common choice
• Lithium Heparin: Avoid when testing lithium levels
• PST (Plasma Separator): Contains gel barrier

• STAT chemistry panels
• Basic metabolic panels (rapid)
• Cardiac markers (emergency)
• Therapeutic drug monitoring
• Point-of-care testing compatibility

• Faster processing: No clotting time required
• Gel separation: Clean plasma layer post-centrifuge
• Stability: Plasma stable on gel barrier
• Emergency use: Ideal for STAT chemistry

• Complete Blood Count (CBC) with differential
• Hemoglobin and Hematocrit (H&H)
• Platelet count and morphology
• Reticulocyte count
• Hemoglobin A1c
• ESR (Erythrocyte Sedimentation Rate)

• EDTA-dependent clumping: Can affect platelet counts
• Proper fill: Maintains correct blood-to-anticoagulant ratio
• Room temperature: Best storage for cell morphology
• Immediate mixing: Prevents microclot formation

• ABO/Rh blood typing
• Antibody screening and identification
• Crossmatching for transfusions
• Direct antiglobulin test (DAT/Coombs)
• Prenatal antibody screening

• Two identifiers: Name + DOB or medical record number
• Bedside labeling: Must label in patient's presence
• Verbal confirmation: Patient states name and DOB
• Documentation: Note collection time and staff signature

• Fasting blood glucose (FBG)
• Oral glucose tolerance test (OGTT)
• 2-hour post-prandial glucose
• Lactate levels
• Blood alcohol content (forensic)

Glycolysis Prevention: Without fluoride, red blood cells continue consuming glucose at ~5-7% per hour at room temperature. Sodium fluoride inhibits enolase enzyme, stopping glycolysis and preserving true glucose levels.

• Lead, Mercury, Arsenic levels
• Zinc, Copper, Selenium
• Aluminum (dialysis monitoring)
• Chromium, Manganese
• Micronutrient analysis