Urine:

Screw cap plastic container (non sterile)  

Lithium heparin plasma:

 Lt green plasma separator (PST) 

• Collect blood sample within 2 hours of urine collection
• Immediatley following blood collection, mix the sample thoroughly by gentle inverting 8 - 10 times, to prevent clotting

Urine:

 Urine aliquot transport vial/tube - 10mL (AHL) 

Plasma:

Lt green Plasma separator (PST) 

Serum:

Gold serum separator (SST) tube 

Gold serum separator (SST) tube:

Immediately following collection, thoroughly mix sample by gently inverting 5 times

Gold serum separator (SST) tube:

1. Allow sample to clot for a minimum of 30 minutes
2. Spin within two (2) hours of sample collection

• Improper labels (unlabeled or mislabeled)
• Hemolysis (some procedures)
• Improper anticoagulant or ratio
• Delay in transport
• Improper storage temperature affecting results
• Inappropriate timing of collection
• Improper container
• Leaking container resulting in compromised specimen
• Quantity not sufficient (QNS)

Fract Excr of Urea results below 35% is suggestive of prerenal azotemia.

The measurement of the FEUrea may be useful in patients with AKI who are taking loop or thiazide diuretics. FEUrea is generally 50 to 65 percent in acute tubular necrosis (ATN) and below 35 percent in prerenal disease, and the effect of diuretics on the FEUrea is less than the effect on FENa.