Methods of Blood Collection Flashcards
(31 cards)
What are the two methods of blood collection?
- Capillary Puncture
- Venipuncture method
What is Capillary Puncture?
- Method of blood collection by skin puncture
- Method of choice in pediatric patients
- Useful in adults with extreme obesity, severe burns, and thrombotic tendencies
What site is capillary puncture collected?
- Distal phalanx of middle of ring finger
- Middle finder is first choice
- Can also be heel, finger, earlobe, or toe
What is the best method of collecting blood?
Venipuncture
- Relative ease makes it a primary source of specimen
What is the equipment necessary for Capillary puncture?
- Sterile gauze pads
- 70% ETOH or Betadine solution
- Lancet
- Capillary tubes or QBCstar
- Bandage
What is the procedure for capillary puncture?
- Arrange equipment
- Wash hands
- Identify, greet, reassure Pt
- Educate Pt
- Massage finger towards fingertip
- Clean fingertip
- Stab using lancet
- Wipe away first drop of blood
- Obtain specimen
- Apply bandage
How many times do you “massage” the finger in preparation for Capillary Puncture?
5-6 times
When using the Lancet, what do you keep in mind?
- Max depth of lancet should be 2 mm
- Use lancet against the grains of the fingerprint
Why do you wipe away the first drop of blood when performing capillary puncture?
Avoid dilution of the sample with tissue fluid
When obtaining a specimen via capillary puncture, what angle do you want to hold the tube from the finger?
15 degrees
How do you want to fill the tube when performing capillary puncture?
- Place tube at 15 degrees
- Keep tube in contact to avoid air bubbles
- Fill tube according to manufactures directions
When performing venipuncture, what sites do you not want to use and why?
- IV sites
It can dilute the specimen or alter test results
What is the equipment associated with venipuncture?
- Sterile gauze pads
- 70% ETOH/betadine solution
- Tourniquet
- Vacutainer needle
- Vacutainer holder
- Vacutainer tubes
What is the procedure for venipunture?
- Position the Pt
- Have Pt sitting/lying
- Use caution so Pt does not fall from chair
- Wash hands
- Assemble equipment
- Identify, great, assure Pt
- Explain procedure
- Apply tourniquet 2-3” above site
- Palpate site
- Clean site
- Perform venipuncture
Detailed needle stick portion of venipunture
- Use thumb to pull back skin
- Insert needle at 15 degree angle, bevel up
- Insert and fill vacutainer
- Remove needle
- Have Pt hold pressure for 3 minutes
What is the anticoagulant used in purple tops?
- Ethylenediaminetetraacetic Acid (EDTA)
When is EDTA typically used?
- CBC
- WBC Differential
Overview of EDTA?
- Most commonly used anticoagulant
- Chelating agent that binds calcium so blood cannot clot
- Does not affect cellular morphology
- Specimens can be refrigerated for approx. 24 hours
What is the powder anticoagulant used in light blue tops?
Sodium Citrate
What is Sodium Citrate commonly used for?
- Prothrombin Time (PT)
- Partial Thromboplastin Time (PTT)
- Chelating agent that binds calcium
What liquid or powder anticoagulant is used in green tops?
Heparin
What is Heparin used for?
- Typically used for plasma studies and chemistry testing
- Ammonia
- Adrenocorticotropic hormone (ACTH)
How does Heparin work?
- It inhibits the clotting enzyme, thrombin, by by creating an antithrombin
- Antithrombin prevents conversion of prothrombin into thrombin
What is special about red tube tops and what are they used for?
- No anticoagulant or additives
- Commonly used for:
- Chemistry
- Serology
- Blood bank
- Other tests requiring serum
