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Collecting specimens
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Collecting and analyzing blood specimens

You may be asked to collect a blood specimen (during emergent situations) from either an arterial line or a central venous catheter.


Observe infection control standards.

Remove “Luer Cap” from 3-way stop-cock closest to the patient. Always use the line that is either being transduced, or one that is not connected to an infusion pump. Twist cap onto sterile needle / nipple to prevent contamination and put it aside. Attach a 10ML “waste syringe” to 3-way stop-cock, withdraw 10 ml of blood for waste. Attach a sample syringe (ABG or 10ml) and withdraw the necessary amount of blood. (Note for ABG: Use appropriate syringe (Heparinised) When taking the ABG sample, make sure there is no air in the syringe when done. Place on ice if immediate analysis not available).

Once specimen collected from the 3-way stop-cock, turn the lever 180* to “open it to air”, disconnect the syringe, and flush the 3-way stop-cock hub clear into a 4X4 gauze. Turn the 3-way stop-cock 90* back, wipe the opening with an alcohol swab, and recap. Flush the line until all blood is cleared.

Attach a needle onto the syringe, and pierce the specimen cap squirting the blood into the tube, initially suction will draw most of the specimen in, but if more need to be injected, aspirate some air first. Always do the PT/T tube 1st (as the other tubes may contain anticoagulants that will affect the PT/T if contaminated.)

        PT/T (INR)                                Blue         (3ml)

        CBC (H/H, Platelets)                        Purple        (3ml)

        Crossmatch                                Purple        (10ml)

        Electrolytes                                Red         (3ml)