Test/Investigation
72-hour fast (DFT)
Site(s) or Laboratory offering Test/Investigation
NNUH (Biochemistry)
Indications
This is a test to determine the body's blood sugar response to prolonged fasting.
Comments/Precautions
Please refer to local trust guidelines for DFT protocols. Please note, insulin/c-peptide will not be assayed if the corresponding glucose result is greater than 2.2 mmol/l. If insulin is required when patient is NOT hypoglycaemic, please contact the lab. Samples will be stored for 6 months. Please ensure all timings are clearly labelled on every sample.
Storage conditions and sample stability between collection and transport to Lab
Send samples to laboratory promptly on ice. All 72 hour fasting samples must be processed urgently. Please refer to the individual tests included in this dynamic function test for more information.
Sample type
Fluoride oxalate (grey top) for glucose and lithium heparin (green top) for insulin/c-peptide. Send to laboratory promptly on ice. Refer to local DFT protocol for timings
Turnaround times (TAT) Urgent/Routine/GP or OPD
Please refer to the individual tests included in this dynamic function test for turn-around times.
If UKAS Accredited Test indicate at which site
Please refer to the individual tests included in this dynamic function test