Bayer HealthCare Rapidlab 800 - Manual (Page 57)

1Ć35 Learning About the System
Sample Source Description
expired gas Expired gas samples may be obtained using a 10 mL syringe. When
used in conjunction with blood gas samples, expired gas samples
provide an assessment of gas exchange and oxygenation status.
capillary blood Capillary blood, when carefully collected under the proper
conditions, resembles arterial blood and can be used for blood gas
studies if the sample limitations are understood.
1 Only small
quantities of blood are required for capillary blood analysis.
Capillary blood can be obtained from the heel, finger, or earlobe. The
area chosen should be prewarmed or stimulated before the puncture
to promote arterial circulation. The puncture should be deep enough
to ensure that blood flow is free and rapid. Take appropriate
precautions to minimize hemolysis, because potassium levels are
falsely elevated in hemolyzed blood.
When collected correctly, arterial, venous, mixed venous, and capillary blood
samples are also suitable for analyte determinations. For further information, refer
to the Bayer Diagnostics brochure Specimen Collection for Critical Blood
Analyte

Testing.
Sample Collection Devices and Anticoagulants
You can use syringes, capillary tubes, and vacuum tubes to collect samples.
Syringes
CAUTION: Never use mineral oil or mercury in syringes since these substances
may alter sample values and damage the system.
Collect blood in Bayer Diagnostics heparinized syringes or equivalent syringes to
satisfy the requirements for blood gas analysis.
The recommended syringe for analyzing samples is the Bayer Diagnostics arterial
sampling device. This sampling device uses a patented, non-exposed, auto-venting
design that does not affect the integrity of the sample. Some auto-venting syringes
contain sodium carboxymethylcellulose (CMC), a substance within the porous
venting mechanism. CMC can dissolve into the sample, compromising sample
integrity. CMC may lower the reported tHb and O
2
Hb levels and elevate the
reported COHb levels.
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