Eurofins Biomnis code

CLEAU

Synonyms

• Free water clearance

Specialty

Analytical Chemistry

Clinical significance

Difference between the urinary flow and the osmolar clearance, i.e. the quantity of water to be added or removed for it to be osmotic to plasma:free water clearance = urinary flow - osmolar clearanceurinary flow (ml/min) = urine volume/period osmolar clearance (ml/min) = urinary osmolarity/serum osmolarity x urinary flowThe free water clearance studies the pituitary-renal axis and measures the quantity of water not bound with electrolytes eliminated or resorbed by the kidney per minute according to the renal activity and anti-diuretic hormone activity.Pathological variations: - insipid diabetes = positive clearance - chronic kidney failure = frequently positive clearance due to urine concentration defect - adrenal insufficiency = constantly negative clearance.

Preanalytics

• Urine + heparin plasma
•   Reftrigerated

• A tube specifically for this analysis : No

Further information

Fasting sample
Specify diuresis
Specify the urine collection time

Methodology

Cryoscopy

Turnaround time

2 days