Urea

Specimen:

5 mL blood in lithium heparin or plain tube.

Method:

Spectrophotometry.

Reference Interval:

Neonate: 1.0-4.0 mmol/L

Adult: 3.0-8.0 mmol/L

Application:

Investigation of renal function.

Interpretation:

Increased levels are seen with reduced glomerular filtration due to renal or pre-renal disease; bleeding into the gastrointestinal tract; hypercatabolic states.

Reduced values are seen in pregnancy; with water retention; with reduced synthesis as a result of decreased protein intake, severe liver disease, or urea-cycle defects.

Reference:

Dossetor JB. Ann Int Med. 1966; 65: 1287-1299.