Anaemia DRAFT

Overview

WHO Definition:

<130g/l Hb in an adult male <120g/l Hb in an adult female; age-dependant in childhood. Anaemia is the commonest haematological disorder seen in general medical practice. Risk factors are extremes of age, being female, pregnant or lactating and although anaemia itself may cause morbidity in the majority of cases it is secondary to an underlying disorder.

Who to refer

Generally, healthy individuals tolerate extreme anaemia well, with cardiovascular status being the major limiting factor. In haemodynamically stable patients without active bleeding, Hb levels between 70 g/L and 90 g/L were well tolerated with equivalent or lower mortality/morbidity outcomes compared with a liberal transfusion trigger of <100 g/L. It is generally recommended that determination of transfusion requirements be based upon severity of illness parameters rather than arbitrary Hb levels.

Consider referral for all those with red flags (see below)

Haematology referral is unlikely to be suitable for:

Patients who are elderly or frail with mild (Hb ≥100g/l) unexplained asymptomatic anaemia (following exclusion of reversible causes and calculate creatinine clearance). Consider monitoring in the community and discussion with a clinical haematology advice & guidance service.

• If transfusion support for symptomatic care is considered appropriate direct arrangements with local Medical Day Care / Ambulatory Care facility may be made. Please see Blood Transfusions page of Remedy.

Clinical Haematology referral is not appropriate for:

• Iron deficiency anaemia - refer to gastroenterology, gynaecology or urology as directed by the clinical assessment. Except in premenopausal women, upper and lower GI investigations are likely to be an appropriate
  • Consider tolerability of iron when prescribing replacement (FeS0₄ 200mg daily or alternate may be adequate). If oral iron replacement is poorly tolerated, consider referral for parenteral iron - can be made from primary care directly to Medical Day Care / Ambulatory Care. Ensure that the patient is counselled about benefits and risks of parenteral iron – information leaflet available in Medical Day Care / Ambulatory Care.
• B12 or folate deficiency – can be managed according to BNF guidance in the community
• Patients with anaemia of chronic disease or renal failure– please consider referral to the relevant specialist team.

Red Flag

 Refer via Haematology 2WW pathways as follows:

• A blood film report that suggests acute leukaemia (often associated with other cytopenias)
• A blood film suggestive of Chronic Myeloid Leukaemia (usually associated leukocytosis)
• Suspected Lymphoma or Myeloma

Urgency of referral will vary depending on various factors including degree of anaemia, rapidity of progression and presence of associated features, as well as frailty of patient.

• A blood film report that suggests a primary haematological disorder.
• With thrombocytopenia or neutropenia.
• Examination shows splenomegaly or lymphadenopathy.
• Reticulocytosis (without obvious bleeding). Raised LDH, bilirubin and low haptoglobin is consistent with haemolysis. Blood film and direct antiglobulin test (Coomb’s test) complete the assessment for this.
• Unexplained, progressive, symptomatic anaemia.
• Amonocloncal protein (also known as paraprotein), abnormal serum free light chain assay or positive urine light chains (Bence Jones protein); usually the laboratory report guides further action.
• Unexplained MCV>105 fl (see macrocytosis).

Before referral

General Asessment points in Primary Care

• The MCV helps to direct investigation for causes of anaemia.
• The reticulocyte count may be useful to differentiate between a red cell production defect (reduced) versus consumption or blood loss (elevated)
• Anaemia may be multifactorial, especially in the elderly
• Transfusions should generally be avoided in patients with reversible causes (e.g. haematinic deficiency or haemolysis) unless there is cardiovascular instability. For other patients the decision to transfuse is based on degree of symptoms directly attributable to anaemia. Erythropoietin may be indicated in specific circumstances after discussion with the relevant specialist (e.g. renal physician or haematologist).
• Assess historical FBC values

Microcytosis/Microcytic anaemia:

 Consider cause. Oral iron replacement is usually appropriate

• Assess serum ferritin – low levels indicate depleted iron stores (still consider this possibility if below 100ug/l).
• If ferritin normal – reconsider iron deficiency if ferritin < 100ug/l, especially if inflammatory condition present); consider anaemia of chronic disease; consider thalassaemia trait.
• Check CRP, iron studies for transferrin saturation or zinc protoporphyrin (ZPP) +/-  reticulocyte count for Ret Hb.  Consider trial of iron replacement if historically normal MCV/Ret Hb is low, then repeat FBC in 6-8 weeks to access response.
• If no previous normal Hb/MCV results consider Hb electrophoresis to assess for β thalassaemia trail. Ethnic background may be informative. Hb electrophoresis will not assess for alpha thalassaemia trait.

 Normocytic anaemia: 

• Assess vitamin B12, folate, ferritin, renal function, liver function tests, reticulocyte CRP.
• Consider assessment of blood film, serum protein electrophoresis.
• If ferritin, vitamin B12 or folate low offer replacement and assess for a cause. If eGFR low consider calculation of creatinine clearance (Cockcroft-Gault) as Cr Cl <40ml/min may cause anaemia.
• Consider clinical haematology advice or referral if no cause found or primary haematological cause likely.
• For older or frail people consider monitoring in the community following exclusion of reversible causes.

Macrocytosis/macrocytic anaemia: 

• Review medical history – abnormal blood loss; diet; change in weight or bowel habit; gastric or terminal ilium surgery; medications; alcohol use, jaundice, liver disease.
• Assess vitamin B12 (not reliable in pregnancy or COCP), liver function tests, reticulocyte count blood film.
• Consider assessment of serum protein electrophoresis, GGT, LDH, TSH.
• *Physiological changes in pregnancy may cause “anaemia”, that may be macrocytic. Investigation is unlikely to be informative unless marked macrocytosis (>105fl) or anaemia (<105g/l) without iron deficiency.
• Offer appropriate replacement if clear evidence of vitamin B12 or folate deficiency. Assess for a causes.
• Consider referral to a clinical haematology service if likely primary haematological condition or no cause established.
• For older or frail people consider monitoring in the community following exclusion of reversible causes.

Referral

URGENT ADVICE: 9am to 5pm via hospital switchboard for haematology SpR. ONLY for emergency advice. Out of hours and weekends – emergency advice may be obtained from the on call haematology clinician via hospital switchboard.

NON-URGENT ADVICE: Use Haematology advice and guidance service which can be accessed through the NHS e-referral system. Your query will be responded by a consultant haematologist within 3 working days.

REFERRAL: via e-RS or cancer fast track pathways as indicated

Minimal information: the referral letter should include abnormal clinical findings (location, size, any associated features) and any abnormal full blood count results or other relevant test results, particularly if these investigations were not done in laboratories of the hospital to which the referral is made.

Cancer fast track: ensure that the location and size of any lymphadenopathy is described. According to NICE guidance and previous section in this guidance.

Other haematology referrals: most new referrals should go to one of the general haematology clinics but may be triaged to a specialist clinic

Iron Infusions - please see Blood Transfusions & Iron infusions (Remedy BNSSG ICB)