Sodium is the major cation of extracellular fluid; it plays an essential role in the normal distribution of water and in the maintenance of osmotic pressure in extracellular fluid compartments. Decreased levels of sodium may be caused by an excessive use of diuretics, prolonged vomiting, a decrease in the intake of sodium in the diet, and metabolic acidosis. Increased levels of sodium may be found in Cushing’s syndrome, severe dehydration, or in high levels of salt intake without an adequate supply of water.

Lt green plasma separator (PST)

Immediately following collection, mix sample thoroughly by gentle inverting 8 - 10 times, to prevent clotting

Spin within two (2) hours of sample collection

Lt green plasma separator (PST)

Gold serum separator (SST) tube

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

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

Gold serum separator (SST) tube

Refrigerated (preferred) - 14 days

Ambient - 14 days

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

Indirect Ion Selective Electrode

136 - 145 mmol/L

<120 mmol/L or >160 mmol/L first only, with 24 hour lookback