Overview
Reflects the number of circulating red blood cells.
Normal Range
- Males: 4.3 - 5.7 x 10¹²/L
- Females: 3.9 - 5.0 x 10¹²/L
Reduced Red Cell Count
Reduced circulating red blood cells.
Causes of Reduced Red Cell Count
Reduced RBC Production
- Haematinic deficiency - B12, folate, iron
- Bone marrow pathology - aplastic anaemia, myeloproliferative diseases, myelofibrosis
- Endocrine - EPO deficiency, hypothyroidism
- Anaemia of chronic disease (infection / inflammation / malignancy)
- Sideroblastic anaemia
- Thalassaemias
Increased RBC Destruction (Haemolysis)
- Immune haemolysis - autoimmune, alloimmune, drug-induced
- Red cell fragmentation - thrombotic microangiopathies, mechanical haemolysis
- Intrinsic RBC disorders - enzymopathies, membranopathies, haemoglobinopathies
- Hypersplenism
- Other - infection, copper, lead, hypophosphataemia
RBC Loss
- Trauma
- Gastrointestinal bleed
- Bleeding from another source e.g. urinary tract
Factitious
- Dilutional - excess fluid administration, pregnancy
Elevated Red Cell Count
Increased circulating red blood cells.
Causes of Erythrocytosis
Primary
- Primary familial erythrocytosis (EPO receptor mutation)
- Polycythaemia vera (JAK2 mutation)
Secondary
- Chronic hypoxia - smoking, chronic lung disease, obstructive sleep apnoea, high altitude
- Renal hypoxia - renal artery stenosis, polycystic kidney disease, post renal transplant
- Drugs - testosterone, anabolic steroids, erythropoietin
- Paraneoplastic syndrome (EPO-producing tumour)
- Congenital - haemoglobinopathies, other mutations
- Idiopathic
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