What Tube for a Glucose (fasting)?
Gray-top tube (sodium fluoride / potassium oxalate). SST or PST are also accepted if separated promptly.
- Additive
- Sodium fluoride / potassium oxalate
- Inversions
- 8–10 times
- Order of draw
- #6 of 6
Collection and handling
- Sodium fluoride stops glycolysis, so cells cannot keep using up the glucose in the tube.
- ARUP: if an SST or PST is used, separate within 2 hours.
Exam tip
The gray top is last in the order of draw. Its additives must not carry into other tubes.
Where it falls in the order of draw
- 1. Blood culture bottles (aerobic + anaerobic) (Culture media)
- 2. Light blue (3.2% sodium citrate)
- 3. Gold / red-gray (SST) or red (Clot activator (SST also has gel))
- 4. Green / light green (PST) (Lithium heparin (PST also has gel))
- 5. Lavender (or pink) (K2EDTA)
- 6. Gray (Sodium fluoride / potassium oxalate)
Full explanation in the order of draw guide.
Tube requirements differ between labs and assays. Always follow your own laboratory's collection manual.
Drill tubes and order of draw until they stick
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