Please do not request B12 levels when a patient is on replacement therapy (high) or pregnant (low), similarly do not request folate levels when a patient is on replacement therapy as spurious values will be obtained. Schilling test for B12 absorption is unlikely to be abnormal when there is a normal blood count or with B12 levels in the intermediate range of 150-200. The combined B12 + intrinsic factor absorption is no longer performed simultaneously with B12 absorption measurement due to withdrawal of radioactive intrinsic factor by the manufacturer.
Serum ferritin is not indicated in uncomplicated iron deficiency but only where you suspect Thalassemia trait or mixed inflammatory (secondary) anaemia. It should be estimated in iron overload and with serum iron and transferrin in suspected haemochromatosis. Confirmation is then by genetic testing.
Tests for haemoglobinopathies and thalassaemia - please check whether these have been performed before and whether the patient has a haemoglobinopathy card.
Hb variants - HbS, C, D, E, and HbF and HbA2 for ß thalassaemia trait (EDTA sample bottle). In emergencies a sickle cell solubility test can be done.
Platelet antibodies no longer performed due to lack of specificity.