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Chapter 43
Blood Specimen Collection
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Capillary Puncture
• Skin puncture or finger puncture– Obtain blood from just
under the surface of the skin
– Ideal for tests requiring only a small amount of blood
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Sites for Capillary Puncture
• Ring finger• Great finger• Lateral sides of the heel on infants
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Performing the Capillary Puncture
• Sterile lancet device is used• Make skin puncture across the fingerprints,
not parallel to them
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Venipuncture
• Surgical puncture of a vein, also called phlebotomy
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Site Selection
• Sites for venipuncture– Most common: the inner
arm at the bend of the elbow
– Back of the palm (for difficult draw)
• Swab area with alcohol
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Applying the Tourniquet
• Tourniquets promote palpation and sometimes visual position of the veins
• Apply three inches above the intended venipuncture site
• Do not leave on patient longer than 1 minute
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Preparing the Patient
• Explain the procedure and answer any patient questions
• Patient instructions– Explain that there will be minimal pain and/or
discomfort, which usually subsides quickly– Relaxing will help speed up the procedure
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Venipuncture Methods
• Vacuum tube and sterile needle– Most popular method of collection– 21-23 gauge needle is generally used– Blood specimen enter directly into test tubes
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Venipuncture Methods
• Sterile needle and syringe– Used when patient has small veins– Usually a 10-20 mL syringe is used
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Venipuncture Methods
• Butterfly – Used for difficult draws– A smaller gauge needle is used– The tourniquet is applied just above the wrist
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Collection Tubes
• Red-stoppered tubes– Range from 3 to 15 mL– Used for whole blood
collection and allowed to clot
– After clotting, blood is spun and serum poured off
• Red/black stoppered tubes– SST separates red cells from serum
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Collection Tubes
• Lavender-stoppered tubes– Contain EDTA– Range from 5 to 10 mL– Used in whole blood collection
• Gray-stoppered tubes– Contains oxylate– Usually 5 mL– Used in blood glucose test
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Collection Tubes
• Blue-stoppered tubes– Usually 5 mL– Used for testing prothrombin times– Must be completely full
• Green-stoppered tubes– Contains heparin– Usually 5 mL– Used to determine several chemical constituents
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Order of Draw
• Yellow• Blue• Red/ Red Black• Green• Lavender• Gray
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Documentation for Specimen Collection
• Lab request form must be completed, sent with specimens, and listed in log book– Date collected– Patient’s full name, DOB, or records number– Date sent to lab– Test(s) requested– Date results received– Test results