• Serum folate <3 microgram/L is indicative of folate deficiency 
• ‘False positive’ reduced serum folate in: 
  
  • normal pregnancy
  • anorexia
  • acute alcohol consumption
  • medications e.g. anticonvulsant therapy. Consult BNF

Precautions

• Low folate may be with low serum cobalamin
  
  • if so, treat with B₁₂ before commencing folic acid 
• If strong clinical suspicion of folate deficiency, despite a normal serum level: 
  
  • exclude cobalamin deficiency
  • measure red cell folate assay 

Specific symptoms for reduced folate

• Reduced sense of taste
• Diarrhoea
• Numbness and tingling in the feet and hands
• Muscle weakness
• Depression

Assess for cause

• Diet (most common cause)
• Alcohol consumption
• Gastrointestinal diseases e.g. 
  
  • coeliac disease, inflammatory bowel disease, liver disease, GI surgery
• Pregnancy status
• Exfoliative skin diseases
• Renal dialysis 
• Medications 
• History/symptoms due to haemolytic anaemia

• Dietary sources of folate
  
  • asparagus, broccoli, brown rice, chickpeas, sprouts, peas 
• Follow schedules outlined in BNF
• Renal dialysis patients, follow renal protocols
  
  • note Renavit® contains 1 mg folic acid. Give after dialysis
  • excess folic acid may cause dynamic bone disease
• Transfusion not indicated in haematinic deficiency unless haemodynamic instability
  
  • see Red blood cell transfusion guideline
  • see Chronic anaemia guideline 

• Monitor reticulocyte count and FBC parameters initially
• Monitor serum folate level as dictated by clinical indication

• Inform GP of:
  
  • cause
  • treatment
  • monitoring required
• If folate deficiency secondary to haemolysis liaise with clinical haematology for follow-up