The use of an inhibitor, i.e. sodium fluoride/oxalate, or rapid separation of the plasma is
recommended to prevent glycolysis due to the presence of erythrocytic enzymes. Blood
glucose values measured with a dry film/test strip system may be erroneous where the
haematocrit values are outside the reference ranges. The ability of certain primates to
store food in their buccal pouches often prevents the true measurement of ‘fasting’
glucose. Plasma glucose levels below 1.7 mmol/L, which would give rise to clinical signs
of hypoglycaemia in man, do not appear to produce similar adverse effects in some other
primate species. With some rodent species, it appears that the animals have to be fasted
for much longer periods than other species to achieve similar reductions of plasma
glucose. This latter observation has led to some debate about the merits of fasting smaller
laboratory animals such as mice and rats prior to blood collection (see Chapter 2).
Hypoglycaemia is apparent in some animals where gastric absorption or food intake has been markedly altered. Blood collection procedures may cause a marked elevation of
plasma glucose where the animal is subject to stress including restraint (Gartner et al.,
1980).