For cartridge testing of blood gases, electrolytes, chemistries, and hematocrits, draw the patient’s blood as described below.

Blood Draw

Completely fill a plain syringe, blood gas heparinized syringe (in the CCATT allowance standard), or a syringe with the minimum volume of heparin to prevent clotting (10 U/mL of blood). Mix a heparinized syringe by rolling it between the palms for at least 5 seconds in two directions, then invert the syringe repeatedly for at least 5 seconds. For best results, test the blood immediately. For samples measuring pH, PCO2, PO2, TCO2, and ionized calcium, sample processing within 10 minutes of blood draw is acceptable; other analytes can be processed within 30 minutes of blood draw if a heparinized syringe was used. If a tourniquet is used for a venous stick, do not leave it on for more than 1 minute; do not draw blood proximal to an IV site.

Criteria for Specimen Rejection

1. There is evidence of specimen
2. Specimens were collected in vacuum tubes with anticoagulants other than lithium or sodium
3. Syringe for pH, PCO2, PO2, or TCO2 has air bubbles in An air bubble stuck only on the plunger will not affect the results.

Precautions: Avoid the Following Circumstances

- Drawing a specimen from an arm with an
- Stasis (tourniquet left on longer than 1 minute before venipuncture).
- Extra muscle activity (fist pumping).
- Hemolysis (alcohol left over puncture site or a traumatic draw).
- Time delays before filling
- Exposing the sample to air when measuring pH, PCO2, PO2, or TCO2.

Cartridge Preparation for Loading Blood Sample

- Prior to using a cartridge, it must be removed from refrigerated storage and kept at room temperature in its protective pouch for at least 5 minutes.
- An entire box of cartridges must be kept at room temperature for 1 hour before a cartridge from the box can be used. Avoid condensation from forming on a cold cartridge as it may prevent proper contact with the analyzer.
- The process for loading the cartridge with blood is detailed in Appendix