Which practice can cause a false decrease in TCO2 if not managed?

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Multiple Choice

Which practice can cause a false decrease in TCO2 if not managed?

The main idea is that CO2 in a blood sample is volatile and can escape into the air if the sample isn’t sealed. Total CO2 (TCO2) reflects the amount of CO2 in the sample, including dissolved CO2 and bicarbonate. When the cap is left open during collection, CO2 diffuses out of the sample into the surrounding environment, so the measured TCO2 is lower than the true value. To avoid this, seal the sample immediately after collection, and if possible, keep it on ice and analyze promptly to preserve the CO2 content. Storing the sample at high temperature, using EDTA as an anticoagulant, or analyzing after several hours can also affect results, but the most direct and consistent way to cause a false decrease in TCO2 is the sample being exposed to air due to an open cap.

The main idea is that CO2 in a blood sample is volatile and can escape into the air if the sample isn’t sealed. Total CO2 (TCO2) reflects the amount of CO2 in the sample, including dissolved CO2 and bicarbonate. When the cap is left open during collection, CO2 diffuses out of the sample into the surrounding environment, so the measured TCO2 is lower than the true value. To avoid this, seal the sample immediately after collection, and if possible, keep it on ice and analyze promptly to preserve the CO2 content.

Storing the sample at high temperature, using EDTA as an anticoagulant, or analyzing after several hours can also affect results, but the most direct and consistent way to cause a false decrease in TCO2 is the sample being exposed to air due to an open cap.

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