Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Pleural fluid acidosis reflects an increase in lactic acid and carbon dioxide production due to a local increase in metabolic activity. The main use of pleural fluid pH is in aiding in the decision to treat pleural infection with tube drainage. Measurement of pH in any other fluid is not likely to be helpful.
Specimen container paediatric:
Arterial blood gas syringe collected anaerobically
Specimen container adult:
Arterial blood gas syringe collected anaerobically
Minimum volume paediatric:
1 mL fluid
Minimum volume adult:
1 mL fluid
Special requirements:
Send to lab ASAP.Samples which are too viscous and/or contain particulate matter after centrifugation are unsuitable for analysis.
Interpretation:
Pleural fluid pH less than 7.3 may suggest malignant effusion, complicated pleural infection, connective tissue disease, tuberculous effusion and oesophageal rupture.
pH less than 7.2 suggests a parapneumonic effusion or empyema and may require drainage.
Reference ranges:
pH > 7.3 considered normal.