Are we appropriately testing for vitamin B12 and folate deficiency?

Abstract

Background:  The most common reason for assessing vitamin B12 and folate status is a clinical suspicion of deficiency along with the haematological abnormality of macrocytic anaemia.However, there is often a lack of a precise clinical or haematological picture to guide the appropriate investigation of these patients. Normal haemoglobin or mean cell volumes are often found, masking the need for appropriate investigation. When abnormal haematological parameters are found, it is often a sign of advanced deficiency. In this study we investigated whether patients with haematological findings of macrocytosis and/or anaemia are appropriately investigated for vitamin B12 and folate deficiencies and whether clinicians request metabolite screening to assist with the diagnosis.

Methods:  This was a retrospective audit of data obtained from the laboratory information system for a six month period at a tertiary academic hospital.  Adult patients with macrocytosis, anaemia or both were selected and laboratory records reviewed to determine whether they were investigated for vitamin B12 and folate deficiency.

Results:  Only 16.2% of patients with macrocytic anaemia, 7.8% of patients with isolated macrocytosis and 6.5% of patients with normocytic anaemia were tested for vitamin B12 and/or folate deficiency. Metabolite assays such as homocysteine and methylmalonic acid were not requested as part of a vitamin status assessment. 

Conclusions:  In our setting, vitamin B12 and folate assessment is a diagnostic dilemma, delaying identification of potentially debilitating disease. Clinicians need to be informed about earlier investigation and of the availability of metabolite screening and their use in establishing early deficiency.