1. Phlebotomy: Venipuncture and Capillary Puncture
Chapter 40
Phlebotomy: Venipuncture and Capillary Puncture

2. Why Collect Blood?
Phlebotomy: for diagnostic purposes or bloodletting as therapeutic measure
Bloodletting dates to ancient Egyptians
Phlebotomy historically used to cure patients with “bad” blood
Also called venipuncture

3. The Medical Assistant’s Role in Phlebotomy
To collect blood as efficiently as possible for accurate and reliable test results
Role varies
Direct contact with patient
Provide high-quality care
Must act professionally

4. Anatomy and Physiology of the Circulatory System
Blood forms in body’s organs and bone marrow
Blood carries oxygen and nutrients to cells and removes waste products and carbon dioxide
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5. Anatomy and Physiology of the Circulatory System
Heart: pumps blood through body
Arteries: blood flows away from heart
Veins: blood flowing back to heart
Capillaries: connecting most arteries and veins

6. Anatomy and Physiology of the Circulatory System
Arteries
Carry blood from heart, carry oxygenated blood (except pulmonary artery)
Normally bright red in color
Elastic walls that expand with surge of blood
No valves
Can feel a pulse

7. Anatomy and Physiology of the Circulatory System
Veins
Carry blood to heart, carry deoxygenated blood (except pulmonary vein)
Normally dark red in color
Thin walls/less elastic
Valves
No pulse

8. Anatomy and Physiology of the Circulatory System
Body contains about 6 liters of blood
45% of blood is formed elements
Erythrocytes
Leukocytes
Thrombocytes (platelets)

9. Anatomy and Physiology of the Circulatory System
55% of blood is liquid
2.5 milliliters (mL) blood will yield about 1 mL serum
Liquid part of blood is plasma
Clotting converts fibrinogen into fibrin

10. Anatomy and Physiology of the Circulatory System
Centrifuge separates serum from blood
Vacuum collection tubes showing serum and plasma
Anticoagulant prevents blood from clotting
Buffy coat: leukocytes and thrombocytes
[FIGURE 40-3]

11. Blood Collection
Most laboratory tests performed on serum, plasma, or whole blood
Serum sample: serum separator vacuum tube with thixotropic gel used
Do not use serum separator tubes for therapeutic drug monitoring (TDM) or toxicology studies

12. Blood Collection Plasma and whole-blood collection
Tubes containing anticoagulants used
Preparing plasma specimen for transport or testing similar to serum preparation

13. Blood Collection Collection of blood specimens
Venipuncture commonly used method
Antecubital area
Median cubital vein
Superficial veins in hands or wrist
Veins in feet or legs
Arteries of arms

14. Venipuncture Equipment
Syringes and needles
Syringes usually made of plastic
Vary in size from 1 mL to 10 mL; Luer-Lok tip
Needles attach to syringes
[FIGURE 40-6A]
(See Table 40-1: Comparison of Blood Collection Methods)

15. Venipuncture Equipment
Syringes and needles
Needles vary in gauge and length
Special needle; multidraw needle
Winged infusion set (butterfly) with safety needle
[FIGURE 40-8]
(See Table 40-2: Needle Gauges Used in Phlebotomy)

16. Venipuncture Equipment
Safety needles and blood collection systems
OSHA requires safety needles
Prevent on-the-job needlestick injuries
Needlestick prevention devices (NPDs)
[FIGURES 40-10B and 40-10C]

17. Venipuncture Equipment
Vacuum tubes and adapters/holders
Vacuum tubes: vacuum-packed test tubes with rubber stoppers
Plain or with added chemicals or substances necessary for appropriate test to be run
Plastic holders or tube adapters used in conjunction with vacuum tubes

18. Venipuncture Equipment
Anticoagulants, additives, and gels
Different tests require different types of blood specimens
Additive:
Anticoagulant to prevent clotting of blood
Chemical to help preserve blood
Substance to accelerate clotting process

19. Venipuncture Equipment
Anticoagulants, additives, and gels
Gel plugs: act as separators between blood cells/clot and serum/plasma
Anticoagulant: chemical substance that prevents clotting; identified by tube color
Clot activators: silica particles on sides of the tubes that initiate clotting process

20. Venipuncture Equipment
Anticoagulants, additives, and gels
When centrifuged, gel changes to liquid
Gel forms solid plug and separates cells/clot from plasma/serum
[FIGURE 40-16]
Separator thixotropic gel tube>>

21. Venipuncture Equipment
Order to draw
Revised Order of Draw published in 2003 by CLSI and is still the standard
Sterile collection bottles need to be filled first to prevent any contamination
After sterile culture tubes drawn, order for other tubes is related to additives in them
(See Table 40-4: Standard Order of Draw— CLSI Guidelines as of December 2008)

22. Venipuncture Equipment
Tourniquets
Constrict flow of blood in arm
Make veins more prominent
Rubber or elastic strip 1 inch wide by 15–18 inches long
Blood pressure cuff may be used instead

23. Venipuncture Equipment
Specimen collection trays
Hold all equipment necessary
Portable
[FIGURE 40-18]

24. Venipuncture Technique
Approaching the patient
Social skills
Technical skills
Administrative skills
(See Table 40-5: Steps in Venipuncture)

25. Venipuncture Technique
Preparing supplies and greeting the patient
Prepare before venipuncture
Place all tubes within easy reach
Keep spare tubes

26. Venipuncture Technique
Patient and specimen identification
Ask patient to state full name
Check wristband if applicable
Label specimen tubes before leaving examination room
Check paperwork against tubes

27. Venipuncture Technique
Patient and specimen identification
Computer label >>
Aliquot specimen>>
[FIGURES 40-19A and 40-19B]

28. Venipuncture Technique
Positioning the patient
Comfortable for patient and health care professional
Selecting the appropriate venipuncture site
Antecubital
Back of hand
Back of wrist (can be painful)
Ankle or foot (provider permission needed)

29. Venipuncture Technique
Applying the tourniquet
Applied 3 to 4 inches above intended puncture site
Tightly enough to slow flow of blood in veins but not so tightly as to prevent flow of blood in arteries
On arm no longer than 1 minute
Remove as soon as blood flow established

30. Venipuncture Technique
Performing a safe venipuncture
Find site that will give best blood return
Palpate vein with tip of index finger
Differentiating between veins, tendons, nerves
Use tourniquet appropriately
Avoid scars and compromised arms

31. Specimen Collection Hand washing critical step Tie tourniquet
Select a vein
Cleanse site firmly with alcohol pad
Allow area to air dry
Put on gloves
Palpate vein

32. Specimen Collection The syringe technique
Ideal for collecting small volumes of blood from fragile, thin, or “rolling” veins
Blood placed in appropriate containers
Order of filling the tubes important
Use a safety system
(See Procedure 40-2: Venipuncture by Syringe)

33. Specimen Collection The syringe technique
Proper hand position to hold syringe >>
[FIGURE 40-21]

34. Specimen Collection The syringe technique
After drawing blood into syringe, activate needle’s safety mechanism, then remove needle and dispose
Connect needleless syringe to transfer device
Insert vacuum tube to device
Allow blood to transfer from syringe to tube
After filling, mix any tubes containing additives

35. Specimen Collection Vacuum tube specimen collection
Improvement over syringe method with only slight variations
Vacuum already in tube
<<Proper hand position
[FIGURE 40-25]

36. Specimen Collection Butterfly needle collection system
Combines benefits of syringe and vacuum tube methods
Used for small and fragile veins that are difficult to puncture
Winged needle inserted at 5- to 10-degree angle then threaded into vein
Works well on children

37. Specimen Collection Blood cultures
Use surgical solution rather than alcohol
Use sterile techniques
Blood collected into special transport bottles
Aerobic bottle filled first, then anaerobic
[FIGURE 40-27]

38. Specimen Collection Patient reactions Vary
MA must anticipate reactions and respond appropriately
If pain persists, discontinue venipuncture
(See Table 40-6: Patient Reactions to Blood Draws)

39. Specimen Collection The unsuccessful venipuncture Stimulate the vein
Change position of needle by rotating needle half a turn
Advance further into vein
Pull back a little
Try another tube
(See Table 40-7: Methods of Vein Stimulation)

40. Specimen Collection The unsuccessful venipuncture
Withdraw needle slowly
Probing of site not recommended
After two attempts, have someone else try
Notify patient’s provider if two MAs unsuccessful

41. Specimen Collection Criteria for rejection of a specimen
Quality-assurance controls for specimen collection and processing
Retesting specimen or collecting another sample
(See Table 40-8: Quality Assurance for Specimen Collection and Processing)

42. Specimen Collection Factors affecting laboratory values
Improper specimen handling and storage
Patient physiologic factors may contribute to inaccurate results
Special handling requirements not met
Patient alters results by certain actions
(See Table 40-9: Factors Affecting Laboratory Results)
(See Table 40-10: Common Laboratory Tests that Require Special Handling)

43. Capillary Puncture Method of obtaining one to several drops of blood
Tests that use blood obtained by capillary puncture
CBC, RBC, and WBC
Hemoglobin and hematocrit
Glucose testing
Phenylketonuria testing

44. Capillary Puncture Capillary blood collection sites
[FIGURES 40-28A and 40-28B]
Capillary blood collection sites

45. Capillary Puncture Preparing capillary puncture site
Promoting circulation
Cleaning and disinfecting >>
[FIGURE 40-30B]

46. Capillary Puncture Performing the puncture Wear appropriate PPE
Perform puncture in one quick, steady movement >>
Wipe away first drop of blood
Collect in capillary tubes or other capillary collection device >>
[FIGURES 40-30C and 40-30F]
(See Procedure 40-5: Capillary Puncture)