Blood Collection, Equipment, Additives, and Order of Draw

1. Blood Collection, Equipment, Additives, and Order of Draw Chapter 7

2. Objectives • Define the key terms and abbreviations listed at the beginning of this chapter. • List, describe, and explain the purpose of the equipment and supplies needed to collect blood by venipuncture. • Compare and contrast antiseptics and disinfectants and give examples of each. • Identify appropriate phlebotomy needles by length, gauge, and any associated color coding.

3. Objectives • List and describe evacuated tube system (ETS) and syringe system components, explain how each system works, and tell how to determine which system and components to use. • Identify the general categories of additives used in blood collection, list the various additives within each category, and describe how each additive works.

4. Objectives • Describe the color coding used to identify the presence or absence of additives in blood collection tubes and name the additive, laboratory departments, and individual tests associated with the various, color-coded tubes. • List the “order of draw” when multiple tubes are being collected and explain why it is important.

5. General Blood Collection Equipment • Blood-Drawing Station • Phlebotomy Chairs • Equipment Carriers • Hand-held • Carts • Gloves • FDA regulates glove quality

6. General Equipment cont. • Antiseptics = prevent or inhibit growth of microbes but does not necessarily kill them • Disinfectants = used to remove or kill microbes on surfaces and instruments • Not typically safe for skin • Hand Sanitizers • Gauze • Bandages/Tape • Needles and Sharps Container

7. Venipuncture Equipment • Vein-Locating Devices • Tourniquet • Needles • Bevel • Shaft • Hub • Lumen • Gauge = number that relates to the diameter of the lumen • Larger the number, the smaller the actual diameter of the needle • 21 Gauge needle is standard • Length = 1 or 1.5 inch • Safety Device – OSHA requires the needle or the equipment it is being used with to have a safety feature

8. Evacuated Tube System (ETS)(Vacutainer) • Most common and CLSI preferred system for collecting blood OSHA requires that the tube holder with needle attached be disposed of as a unit Called multisample needle because it allows multiple tubes of blood to be collected during a single venipuncture Tube size is based on age of patient, amount of blood needed, and size and condition of patient’s vein

9. Evacuated Tube • Vacuum = Evacuated tubes fill with blood automatically due to negative pressure in them • Premeasured by the manufacturer so that the tube will fill with exact amount of blood indicated • Premature loss of vacuum can occur and the tube will fail to fill with blood • Can result in a “Short Draw” = underfilled tube

10. Evacuated Tubes • Additive = substance placed within tube • Underfilled tube that contains additive will have an incorrect additive-to-blood ratio which can lead to inaccurate test results • Expiration Dates

11. Syringe System • Used for patients with small or difficult veins When drawing venous blood, slowly pull back the plunger to create a vacuum that causes the barrel to fill with blood Syringe transfer device allows the safe transfer of blood into the tubes without using the syringe needle

12. Winged Infusion Set (Butterfly) • Used for collecting blood from small or difficult veins • Hand veins • Pediatric patients • 23 gauge is most commonly used

13. Blood Collection Additives • Never transfer blood from one additive tube into another additive tube as it will interfere with the test • Even if the same additive, mixing together will create an excess of additive • Invert the tube 3-8 times immediately after collection • Never shake as it can cause hemolysis

14. Anticoagulants • Substances that prevent blood from clotting • Chelating or precipitating calcium so it is unavailable for the coagulation process • Inhibiting thrombin needed to convert fibrinogen to fibrin in the coagulation process

15. Anticoagulants • EDTA = prevents by chelating calcium • Used in hematology since it preserves cell morphology and inhibits platelet aggregation • Mix immediately to prevent microclots or platelet clumps otherwise will need to recollect • Need to fill tubes completely otherwise it will cause RBCs to shrink due to excess EDTA and changes the CBC results • Also used in blood bank

16. Anticoagulants • Citrates = prevent coagulation by chelating calcium • Sodium Citrate (light blue tubes) is used for coagulation tests (PT or APTT) since it preserves the coagulation factors well • Coag tests are performed on plasma • Critical 9:1 ratio of blood to anticoagulant so need to fill them completely • Underfilled tubes cause false prolonged clotting times and will be rejected • Needs immediate mixing

17. Anticoagulants • Heparin = prevents clotting by inhibiting thrombin formation • Heparinized plasma is used for stat chemistry tests • Mix immediately • 3 heparin formulations: Ammonium, Lithium, and Sodium • Lithium causes the least interference in chemistry testing and is most widely used anticoagulant for plasma and whole-blood chemistry tests

18. Anticoagulants • Oxalates = prevent clotting by precipitating calcium • Potassium oxalate is most widely used (gray) • Commonly added to tubes containing glucose preservatives to provide plasma for glucose testing • Need immediate mixing • Fill completely since excess oxalate can cause hemolysis and release hemoglobin into plasma

19. Special-Use Anticoagulants • Acid Citrate Dextrose (ACD) = prevents clotting formation by binding calcium • Used in immunohematology tests such as DNA testing and human leukocyte antigen (HLA) phenotyping needed in paternity evaluation and for transplant compatibility • Yellow • Needs immediate mixing

20. Special-Use Anticoagulants • Citrate-Phosphate Dextrose (CPD) = prevents clotting by chelating calcium • Used for collecting units of blood for transfusion • Sodium PolyanetholSulfonate (SPS) = prevents clotting by binding calcium • Used for blood culture collection, it reduces the action of a protein called complement that destroys bacteria, slows down phagocytosis, and reduces activity of certain antibiotics • Need immediate mixing

21. Antiglycolytic Agents • Substance that prevents glycolysis (breakdown of glucose by blood cells) • If not prevented, the glucose concentration in a specimen decreases at a rate of 10 mg/dL per hour • Most common antiglycolytic agent is Sodium Fluoride (Gray) – it preserves glucose for up to 3 days

22. Clot Activators • Substance that enhance coagulation • Include substances that provide more surface for platelet activation such as glass (silica) particles and inert clays like celite, and clotting factors such as thrombin • Silica particles are the clot activator in Serum Separator Tubes (SST) and plastic red-top tubes, cause blood to clot within 15-30 min • Thrombin causes clotting within 5 min • Require mixing

23. Thixotropic Gel Separator • Inert (nonreacting) substance contained in or near the bottom of certain blood collection tubes • When a specimen in a gel tube is centrifuged, gel undergoes a change in viscosity and moves to a position between the cells and the serum forming a physical barrier between • Physical separation prevents cells from continuing to metabolize substances, such as glucose, in the serum • Different color and name depending upon company

24. Trace-Element-Free Tubes • Royal blue stoppers indicate trace element free tubes • Tubes are made of materials that are free of trace element contamination and are used for trace element tests, toxicology studies, and nutrient determinations • Contain EDTA, heparin, or no additive • Tube labels are color-coded to indicate the type of additive

25. Order of Draw • Filling tubes in wrong order can lead to interference in testing from additive carryover, tissue thromboplastin, or microbes • Tissue thromboplastin is a substance present in tissue fluid that activates a coagulation pathway and can interfere with coag tests • Discard tube should be drawn when using a butterfly needle if a coagulation tube is the first or only to be drawn due to the air in the tubing

26. Order of Draw • Microbe Contamination • Blood Cultures detect microbes in the blood and require special site cleaning measures prior to collection to prevent contamination from bacteria normally found on the skin • Sterile bottles and are drawn first

27. Order of Draw • Sterile tube (blood culture) • Blue top coagulation tube • Serum tube with or without gel or clot activator • Heparin tube with or without gel plasma separator • EDTA tube • Glycolytic inhibitor tube

28. Order of Draw

29. Syringe Order of Draw • Obsolete – do NOT need to know! • Use the same Order of Draw