CLINICAL CHEMISTRY LABORATORY SPECIMEN COLLECTION AND HANDLING BLOOD SPECIMEN COLLECTION TYPES OF BLOOD SPECIMEN • Venous Whole Blood o For hematology, immunohematology o Only used in Chemistry for HbA1c determination. ▪ Aka glycosylated hgb/glycated hgb ▪ Reflects the average blood glucose level over the previous three months. o Usually used with tubes with anticoagulants • Serum o Chemistry and Immunology/Serology o Liquid part of clotted blood o Most common specimen used in Clinical Chemistry • Plasma o For hematology o Used in chemistry, only if serum is not available • Arterial Blood o For Chemistry o Used for blood gas analysis and pH measurement o Collected by respiratory therapists and physicians • Capillary blood o Rarely used due to difference in analyte concentration BLOOD COLLECTION MATERIALS • Personal Protective Equipment o • Tourniquet • Antiseptics • Syringe/Evacuated Tube System • Evacuated tubes • Requisition forms • Waste receptables • Gauze pad/Cotton ball PERSONAL PROTECTIVE EQUIPMENT • Laboratory Gown • Masks • Goggles/Face shields • Gloves TOURNIQUET • Used as vein compressor • Temporarily Prevents venous blood from returning to heart • Allows the vein to become easily palpable because blood accumulates ANTISEPTICS • 70% Ethyl alcohol - most commonly used • 70% Isopropyl alcohol • Benzalkonium chloride • Chlorhexidine gluconate • Hydrogen peroxide • Povidone-iodine • Tincture iodine • Alcohol is not used for blood alcohol determination test; use instead non-alcohol antiseptics o Use soap and water for cleaning puncture site • For chloride test, do not use Benzalkonium chloride • Proper puncture site cleaning for blood culture specimen collection o First, use 70% Ethyl alcohol o Next, rub Povidone-iodine o Finally, use alcohol o Alcohol → iodine → alcohol o To ensure normal flora is cleaned to prevent contamination SYRINGE/EVACUATED TUBE SYSTEM • Syringe : o Syringe needle – with plastic hub attached designed to fit onto the barrel. ▪ Some have protection devices – hypodermic needle ▪ Hub is an indicator whether a vein is hit o Syringe – divided into graduated barrel and plunger ▪ Barrel – graduated into mL or cc ▪ Plunger – fits tightly within the barrel creating a vacuum when retracted • Evacuated Tube System o Multi-sample needle – aka double pointed needle; allows collection of multiple tubes during venipuncture o Tube holders - plastic cylinder with a small opening for a needle at one end and a large opening for tubes
EVACUATED TUBES • May contain none to more than one additive/s depending on the test ordered. • Universally color-coded • Forms of additives: Liquid, Spray-dried, or Powdered Stopper Color Additive Department(s) Light blue Sodium citrate Coagulation Red (glass) None Chemistry, blood bank, serology/ immunology Red (plastic) Clot activator Chemistry Red/light gray (plastic) Nonadditive NA (Discard tube only) Red/black (tiger) Gold Red/gold Clot activator and gel separator Chemistry Green/gray Light green Lithium heparin and gel separator Chemistry Green Lithium heparin Sodium heparin Chemistry Lavender Pink EDTA Hematology Blood bank Gray Sodium fluoride and potassium oxalate Sodium fluoride and EDTA Sodium fluoride Chemistry Orange Gray/yellow Thrombin Chemistry Royal blue None (red label) EDTA (lavender label) Sodium heparin (green label) Chemistry Tan (glass tube) Tan (plastic) Sodium heparin EDTA Chemistry Yellow Sodium polyanethol sulfonate (SPS) Microbiology Yellow Acid citrate dextrose (ACD) Blood bank/ Immunohematology ORDER OF DRAW • A special sequence of tube collection that reduces the risk of specimen contamination by microorganisms and additive carry over ORDER OF DRAW TUBE STOPPER COLOR 1. Blood culture tubes Yellow (SPS) 2. Coagulation tubes Light Blue Top 3. Serum tube with no additives Red (Glass) 4. Serum tube with additives, SST Red/Black, Gold, Red/Gold 5. Plasma Separator Tubes Heparin Light Green, Green/Gray Green 6. EDTA tubes Plasma Preparator Tubes Oxalate/Fluoride tubes Lavender/Purple, Pink Pearl Top Gray top • Pink tube - for blood banking only, with special marking for crossmatching from the American Association of Blood Banking PREPARATION OF PLASMA AND SERUM SERUM VS PLASMA SERUM PLASMA Definition Clear yellowish liquid part of a clotted blood Hazy and yellowish liquid part of unclotted blood Clotting factors present <20% Factor II (Prothrombin) only All are present Water content 90% 92-95% Method of Separation Spinning of blood after clotting Spinning of blood before clotted Use of anticoagulant Not needed Required Density 1.024 ng/mL 1.25 ng/mL • Serum is clearer than plasma o Plasma contains clotting factors which are proteins that cause turbidity PROCEDURE 1. Collect blood from the patient's vein. 2. Transfer the collected blood in red top tube & EDTA tube. 3. Let the blood samples stand for 15 minutes at room temperature to allow the blood to clot. o EDTA tube may not be left standing o Only red top tube requires standing for clotting 4. Using clean applicator stick, gently swirl the side of the tube for the clotted blood. 5. To the EDTA tube, invert the tube gently for eight times to ensure adequate mixing of blood with the anticoagulant. 6. Centrifuge blood at 2,000-2,500 rpm for 10 minutes. Keep container stopper to prevent evaporation. 7. Separate the yellow fluid both tubes and transfer to a clean dry test tube. 8. Compare the appearance of serum and plasma in terms of clarity of the specimen.
• Purple top - plasma • Red top - serum • If centrifugating one tube only, use a balancer. A balancer is a tube similar to the tube being tested which contain the same amount of liquid. • The two must be placed opposite each other. • Separation of packed RBC • EDTA/purple t ALIQUOT ALIQUOT • Separating the serum/plasma from the packed red cell to a separate tube • Separating a portion of serum/plasma to a separate tube TYPES OF SAMPLES • Hemolyzed - rupture of RBCs so, Hgb released from RBCs o Cause reddish discoloration of plasma/serum o Significantly affect results • Icteric - serum appears yellow due to high bilirubin o Jaundice - liver disease causing high bilirubin o Icteric - dark yellow discoloration of serum/plasma due to Jaundice • Lipemic - serum appears milky or turbid due to high lipid o Proteins tend to float in plasma causing turbidity
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Clinical Chemistry Lab - 01 Specimen Collection and Handling