Pleural fluid
Balanced heparin syringe
(*Please note that different brands of syringe with different size and heparin content are used in NTEC hospitals.)
Minimum pleural fluid volume: 0.6 mL (using 1 mL syringe containing 30 IU balanced lithium heparin)
Minimum pleural fluid volume: 1.6 mL (using 3 mL syringe containing 80 IU balanced lithium heparin)
Authorisation code required
No
24 Hr available service
Yes
Precaution
Pleural Fluid Taking Procedure
- Appropriate volume of pleural fluid 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 pleural fluid 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.
Method
Ion selective electrodes
Reference interval
Refer to result interpretation section.
Clinical indication
Pleural fluid pH is of the greatest value for the assessment of patients whose pleural effusion is due to respiratory infection.
Result interpretation
As the test has not been validated for diagnostic use in pleural fluid, please interpret the result with caution. In general, pleural pH of less than 7.3 often indicates an exudative effusion secondary to malignacy; empyema; connective tissue diesease, such as rheumatoid arthritis, tuberculosis, and esophageal rupture; or hemothorax.
Measurement of uncertainty
Not applicable
Frequency of measurement
Urgent