Practical considerations

Collaboration with a research group experienced in the DLW technique is strongly recommended.

The method requires rigorous attention to detail at every stage
A readymade batch dose of DLW i.e. where deuterium and 18O have been mixed can be useful when dosing a series of subjects
Batches should be autoclaved for 10 minutes to ensure no bacterial contamination
A sample of the each stock dose should be frozen as the reference for mass spectrometry analysis
Dosing is usually done on a per kg body weight basis e.g. 18O at 0.125g/kg and 2H at 0.05g/kg, note the concentration of the isotopes. In obese subjects due to a higher fat mass it may be sensible (and more economical) to dose on estimated total body water assuming that 65% of body weight is water

Subjects

A baseline urine sample is VITAL to the measurement
If a subject forgets to bring a sample collect another prior to dosing
Subjects should be supplied with urine containers which are labelled Day 1- day 10 with the date on with a space for the time to be recorded
Subjects should also record the date and time of the urine samples on a log
Subjects should be instructed to collected a urine sample every day for 10 days after dosing and place into the freezer
Urine should not be collected from the first void in the morning
Subjects should not completely fill the container with urine as it will be frozen and will expand
Subjects should be reassured that if they forget one urine sample to carry on to day 10 regardless
Ensure the urine samples are collected and frozen immediately after the collection period ends
Subjects must record any episodes of vomiting or diarrhoea