Anaemia

Haematology · Abnormal laboratory result · updated 2026-11-08

BioMG follows French guidelines. Adapt it to the guidelines and the tests available where you practise.

Frequency: In France, about 7% of women of childbearing age are anaemic, 4% of them from iron deficiency (Esteban 2014-2016) ^[1].

Microcytic anaemia (MCV < 80 µm3): initial tests

Fasting sample.

Serum ferritin
CRPif neededWhen the clinical picture does not suggest iron deficiency; it can be dispensed with in case of a history of iron deficiency or heavy menstrual bleeding.

Detailed explanation and international comparison (in French): read it in English (machine translation)

Fasting sample.

CRP
Transferrin saturation
haemoglobin electrophoresisif neededLooking for thalassaemia depending on the context, with microcytosis and normal or raised ferritin.
Blood leadif neededSuspected lead poisoning (lead exposure).
Vitamin B6if neededContext of alcoholism (vitamin B6 deficiency possible).

Detailed explanation and international comparison (in French): read it in English (machine translation)

Detailed explanation and international comparison (in French): read it in English (machine translation)

Fasting sample.

Detailed explanation and international comparison (in French): read it in English (machine translation)

Fasting sample.

Blood film
Unconjugated bilirubin
Haptoglobin
LDH
Direct antiglobulin test (direct Coombs test), before any transfusionThe PNDS (French national protocol for diagnosis and care) for AIHA makes it the GP's diagnostic test: a positive result, with haemolysis, confirms the autoimmune nature; to be taken before any transfusion ^[10]. Prescribed straight away to avoid a second blood draw.
Thin and thick blood filmif neededStay in a malaria-endemic area: the film may show parasitised red cells ^[10,11]. Malaria is also among the rare infectious causes of AIHA ^[10]: testing for it does not depend on the result of the direct antiglobulin test.
Haemoglobin electrophoresis, G6PD assayif neededHaemolysis with a negative direct antiglobulin test: sickle cell disease or another haemoglobinopathy (electrophoresis), or G6PD deficiency, whose flares are triggered by many oxidant drugs ^[10]; in children, the PNDS adds pyruvate kinase measurement and the EMA test ^[11].
Urine microscopy and culture (if dark urine and dipstick positive for blood)if neededIntravascular haemolysis: the urine dipstick detects globin and wrongly reads "blood"; urine microscopy and culture rules out haematuria ^[10].

Detailed explanation and international comparison (in French): read it in English (machine translation)

Fasting sample.

TSH
Vitamin B9 (folate)
Vitamin B12
Serum creatinine with eGFR
AST
ALT
GGT
Serum protein electrophoresis
Reticulocyte count (if the cause is not obvious)if needednon-French guidelineFirst test in macrocytosis, with the blood film and vitamin B12, for two American family medicine reviews (2009 and 2018) ^[7,13]: a raised reticulocyte count points to bleeding or haemolysis ^[13] (see the tab “Regenerative normocytic anaemia”). The page “Isolated macrocytosis” includes it from the outset. The Scottish NHS Lothian guide also requests it from the outset ^[14].
Blood film (if the cause is not obvious)if needednon-French guidelineFirst test in macrocytosis for two American family medicine reviews (2009 and 2018) ^[7,13]: it looks for megaloblastosis (macro-ovalocytes, hypersegmented neutrophils) ^[13]; an abnormal blood film raises the possibility of a myelodysplastic syndrome or haematological malignancy and calls for haematology advice ^[7]. The Scottish NHS Lothian guide also requests it from the outset ^[14].

Detailed explanation and international comparison (in French): read it in English (machine translation)

Reticulocyte count
Serum ferritin
CRP (if fever, recent infection or suspected inflammatory disease)if neededFever, recent infection or suspected inflammatory disease: ferritin may then be normal or raised despite iron deficiency ^[16].
Haemoglobin electrophoresis (if microcytosis with normal ferritin, or child originating from a region with a high prevalence of haemoglobinopathies)if neededMicrocytosis without iron deficiency: look for beta-thalassaemia (raised HbA2) ^[17]; see the page “Microcytosis without anaemia”. Migrant child from sub-Saharan Africa, North Africa, the Middle East, South-East Asia, the intertropical zone of Latin America or the Caribbean: screening recommended, possibly after correction of iron deficiency ^[18].
Blood lead (if possible lead exposure)if neededPossible lead exposure: old deteriorating paint in the home or childcare setting, tap water, industrial sources, diet, occupational or leisure activities of the child or parents ^[19]. In a newly arrived migrant child, blood lead recommended before age 16 ^[18].

Detailed explanation and international comparison (in French): read it in English (machine translation)

Serum iron, alone or with ferritin: iron alone is less informative than ferritin, and added to ferritin it provides no additional information ^[16].

Sources (37)