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:
The serous body cavities contain a small amount of fluid that is an ultrafiltrate of plasma. When production and resorption of this ultrafiltrate are not balanced, fluid may accumulate, resulting in an effusion. Effusions may be classified as transudates or exudates. Transudates are usually bilateral and arise from either increased capillary hydrostatic pressure or decreased oncotic pressure secondary to congestive heart failure, fluid overload, cirrhosis or hypoalbuminemia. Exudates are usually unilateral and result from increased capillary permeability or decreased lymphatic resorption associated with infection, connective tissue disease, pancreatitis or cancer. Fluid LDH can, using Light’s criteria, be used to differentiate between transudates and exudates.
Specimen container paediatric:
Plain universal container
Specimen container adult:
Plain universal container
Minimum volume paediatric:
1 mL fluid
Minimum volume adult:
1 mL fluid
Special requirements:
Samples which are too viscous and/or contain particulate matter after centrifugation are unsuitable for analysis.
Reference ranges :
Fluid is exudate if one of the following Light’s criteria is present:
Fluid protein/serum protein ratio greater than 0.5
Fluid lactate dehydrogenase (LDH)/serum LDH ratio greater than 0.6
Fluid LDH level greater than two-thirds the upper limit of the laboratory’s reference range of serum LDH