Arterial blood / Venous blood
Balanced heparin syringe
(*Please note that different brands of syringe with different size and heparin content are used in NTEC hospitals.)
Minimum blood volume: 0.6 mL (using 1 mL syringe containing 30 IU balanced lithium heparin)
Minimum blood volume: 1.6 mL (using 3 mL syringe containing 80 IU balanced lithium heparin)
Authorisation code required
No
24 Hr available service
Yes
Precaution
Blood Taking Procedure
- Appropriate volume of blood should be collected anaerobically in a special balanced heparin syringe. (Collect 0.6 mL blood for 1 mL syringe and 1.6 mL for 3 mL syringe so that the final concentration of the balanced heparin in sample is 50 IU/mL.)
- Dispose the needle, tap syringe to move air bubble to the top and slowly advance plunger to expel air from sample, and then re-cap the syringe with a cap.
- To ensure thorough mixing of blood with heparin, hold syringe in hand and rotate back and forth for 20 to 30 sec.
- Send the blood sample in ice bath to the laboratory immediately for analysis.
Please provide information of O2 therapy via GCRS.
Method
Selective electrodes
Reference interval
Assumption of the derived
results:
Patient temperature = 37 °C
Haemoglobin = 14.5 g/dL
| pH | 7.35 - 7.45 | |
| pCO2 | Adult male | 4.7 - 6.4 kPa |
| Adult female | 4.3 - 6.0 kPa | |
| pO2 | 11.0 - 14.4 kPa | |
| Total CO2 | Arterial | 19 - 24 mmol/L |
| Venous | 22 - 26 mmol/L | |
| Actual bicarbonate | Arterial | 18 - 23 mmol/L |
| Venous | 21 - 25 mmol/L | |
(Source: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics 4th Edition, USA Elsevier Saunders, 2006: 2259, 2286, 2289)
Clinical indication
Assessment of cardiopulmonary function, acid-base balance.
Result interpretation
Decreased pO2 is seen with hypoventilation, ventilation / perfusion mismatch, alveolar-capillary block and right to left shunts.
Increased pO2 may be seen with hyperventilation or oxygen therapy.
Measurement of uncertainty
Frequency of measurement
Daily