Haemolytic Anaemia - Hyperexcision

Last updated: March 25, 2026

Haemolytic anaemia is caused by the destruction of red blood cells at an accelerated pace beyond the capacity of the bone marrow to compensate. Usually, a normocytic picture is present.

Haemolytic anaemia

	Association	Coombs	Other tests	Treatment
Warm AIHA	Autoimmune condition, Lymphoma	Positive	–	Corticosteroids
Cold AIHA	Infection and exposure to cold	Positive	Cold agglutinin titer	Avoid cold
Drug-induced AIHA	Drug exposure (cephalosporin #1)	Variable	–	Remove offending drug
Hereditary spherocytosis	Splenomegaly and FHx	Negative	Spherocytes in PBF	Splenectomy if severe
Paroxysmal nocturnal haemoglobinuria	Cola-coloured urine in the morning +/- pancytopenia, thrombocytopenia	Negative	Flow cytometry for CD55/59	Eculizumab
G6PD deficiency	Male, Intermittent hemolysis following oxidant	Negative	Heinz bodies and bite cells in PBF	Avoid oxidants

Classification of hemolytic anemia

Classification	Examples
Intrinsic hemolytic anemia	Membranopathy, Enzymopathy, Hemoglobinopathy
Extrinsic hemolytic anemia	Autoimmune and alloimmune hemolysis, Mechanical destruction, Toxin-mediated destruction, Hypersplenism

Mechanism of RBC destruction

Mechanism	Description
Intravascular hemolysis	Hemolysis in blood vessels
Extravascular hemolysis	Hemolysis that occurs in the spleen or liver

Coombs positive vs Coombs negative hemolytic anaemia

Coombs	Examples
Coombs (+)	Warm and Cold autoimmune hemolytic anemia, Drug-induced hemolytic anemia
Coombs (-)	Hereditary spherocytosis, Paroxysmal Hemoglobinuria, Glucose-6-Phosphate deficiency, Sickle cell disease

Signs and symptoms
- Symptoms of anaemia
- Splenomegaly – due to trapping and breakdown of RBCs in the spleen
- Jaundice and pruritus – due to degradation of hemoglobin into bilirubin)
- Gallstones – due to hyperbilirubinemia
- Hemosiderinuria – due to destruction of RBCs
- Constitutional symptoms in acquired hemolytic anaemia
  - Fever
  - Weakness
  - Chills
Investigations
- Complete blood count
  - Decreased RBC count
  - Decreased Hb
  - Decreased HCT
  - Normal MCV
  - Elevated WBC
  - Decreased Platelets in MAHA
- Reticulocyte count
  - Elevated reticulocyte count
- Peripheral blood film
  - Reticulocytosis
  - Intravascular hemolysis
    - Heinz bodies (G6PD deficiency)
    - Schistocytes (MAHA and macroangiopathic haemolytic anemia)
    - Intracellular organisms (malaria, babesiosis, bartonellosis)
  - Extravascular hemolysis
    - Spherocytes (Hereditary spherocytosis and immune-mediated hemolysis)
    - RBC agglutination in CAD
    - Sickle cells in sickle cell disease
    - Target cells in sickle cell disease, thalassemia, and HbC disease
    - Teardrop cells in thalassemia
    - Hb Crystals in HbC disease
    - Smudge cells (Gumprecht shadows) in CLL
- Serum studies
  - Decreased haptoglobin
  - Increased LDH
  - Elevated indirect bilirubin
- Urinalysis
  - Haemoglobinuria
  - Hemosiderinuria
  - Urobilinogen
- Coombs test
  - Positive Coombs test = autoimmune process

Reference Intervals ›

Biochemistry

ACTH	P: <80 ng/L
ALT	P: 5–35 U/L
Albumin	P: 35–50 g/L
Aldosterone	P: 100–500 pmol/L
Alk. phosphatase	P: 30–130 U/L
α-Amylase	P: 0–180 IU/dL
α-Fetoprotein	S: <10 kU/L
Angiotensin II	P: 5–35 pmol/L
ADH	P: 0.9–4.6 pmol/L
AST	P: 5–35 U/L
Bicarbonate	P: 24–30 mmol/L
Bilirubin	P: 3–17 μmol/L
BNP	P: <50 ng/L
CRP	P: <10 mg/L
Calcitonin	P: <0.1 mcg/L
Calcium (ionized)	P: 1.0–1.25 mmol/L
Calcium (total)	P: 2.12–2.60 mmol/L
Chloride	P: 95–105 mmol/L
Cholesterol	P: <5.0 mmol/L
VLDL	P: 0.128–0.645 mmol/L
LDL	P: <2.0 mmol/L
HDL	P: 0.9–1.93 mmol/L
Cortisol AM	P: 450–700 nmol/L
Cortisol Midnight	P: 80–280 nmol/L
CK ♂	P: 25–195 U/L
CK ♀	P: 25–170 U/L
Creatinine	P: 70–100 μmol/L
Ferritin	P: 12–200 mcg/L
Folate	S: 2.1 mcg/L
FSH	P: 2–8 U/L ♂; >25 menopause
GGT ♂	P: 11–51 U/L
GGT ♀	P: 7–33 U/L
Glucose (fasting)	P: 3.5–5.5 mmol/L
Growth hormone	P: <20 mu/L
HbA1C (DCCT)	B: 4–6%
HbA1C (IFCC)	B: 20–42 mmol/mol
Iron ♂	S: 14–31 μmol/L
Iron ♀	S: 11–30 μmol/L
Lactate (venous)	P: 0.6–2.4 mmol/L
Lactate (arterial)	P: 0.6–1.8 mmol/L
LDH	P: 70–250 U/L
LH	P: 3–16 U/L
Magnesium	P: 0.75–1.05 mmol/L
Osmolality	P: 278–305 mosmol/kg
PTH	P: 0.8–8.5 pmol/L
Potassium	P: 3.5–5.3 mmol/L
Prolactin ♂	P: <450 U/L
Prolactin ♀	P: <600 U/L
PSA	P: 0–4 mcg/mL
Protein (total)	P: 60–80 g/L
Red cell folate	B: 0.36–1.44 μmol/L
Renin (erect)	P: 2.8–4.5 pmol/mL/h
Renin (recumbent)	P: 1.1–2.7 pmol/mL/h
Sodium	P: 135–145 mmol/L
TBG	P: 7–17 mg/L
TSH	P: 0.5–4.2 mU/L
T4	P: 70–140 nmol/L
Free T4	P: 9–22 pmol/L
TIBC	S: 54–75 μmol/L
Triglycerides	P: 0.50–2.3 mmol/L
T3	P: 1.2–3.0 nmol/L
Troponin T	P: <0.1 mcg/L
Urate ♂	P: 210–480 μmol/L
Urate ♀	P: 150–390 μmol/L
Urea	P: 2.5–6.7 mmol/L
Vitamin B12	S: 0.13–0.68 nmol/L
Vitamin D	S: 50 nmol/L

Arterial Blood Gases

pH	7.35–7.45
PaCO₂	4.7–6.0 kPa
PaO₂	>10.6 kPa
Base excess	±2 mmol/L

Urine

Cortisol (free)	<280 nmol/24h
Hydroxyindole acetic acid	16–73 μmol/24h
Hydroxymethylmandelic acid	16–48 μmol/24h
Metanephrines	0.03–0.69 μmol/mmol cr.
Osmolality	350–1000 mosmol/kg
17-Oxogenic steroids ♂	28–30 μmol/24h
17-Oxogenic steroids ♀	21–66 μmol/24h
17-Oxosteroids ♂	17–76 μmol/24h
17-Oxosteroids ♀	14–59 μmol/24h
Phosphate (inorganic)	15–50 mmol/24h
Potassium	14–120 mmol/24h
Protein	<150 mg/24h
Protein/creatinine ratio	<3 mg/mmol
Sodium	100–250 mmol/24h

Haematology

WCC	4.0–11.0 ×10⁹/L
RBC ♂	4.5–6.5 ×10¹²/L
RBC ♀	3.9–5.6 ×10¹²/L
Hb ♂	130–180 g/L
Hb ♀	115–160 g/L
PCV ♂	0.4–0.54 L/L
PCV ♀	0.37–0.47 L/L
MCV	76–96 fL
MCH	27–32 pg
MCHC	300–360 g/L
RDW	11.6–14.6%
Neutrophils	2.0–7.5 ×10⁹/L (40–75%)
Lymphocytes	1.0–4.5 ×10⁹/L (20–45%)
Eosinophils	0.04–0.44 ×10⁹/L (1–6%)
Basophils	0–0.10 ×10⁹/L (0–1%)
Monocytes	0.2–0.8 ×10⁹/L (2–10%)
Platelets	150–400 ×10⁹/L
Reticulocytes	0.8–2.0% / 25–100 ×10⁹/L
Prothrombin time	10–14 s
APTT	35–45 s

Paediatric

Pulse Rate (bpm)
Neonate	140–160
Infant <1yr	120–140
1–5 years	110–130
5–12 years	80–120
>12 years	70–100
Respiratory Rate (tachypnoea)
0–2 months	≥60/min
2–12 months	≥50/min
1–5 years	≥40/min
>5 years	≥30/min
Blood Pressure (mmHg)
Term	65/45
1 year	75/50
4 years	85/60
8 years	95/65
10 years	100/70
Weight Formulas
3–12 months	(a + 9)/2 kg
1–6 years	2a + 8 kg
>6 years	(7a − 5)/2 kg
Haemoglobin (g/dL)
Term newborn	13–20
1 month	11–18
2 months	10–15
1–2 years	10–13
>2 years	11–14
MUAC (6 months–5 years)
Obese	>17.5 cm
Normal	13.5–17.4 cm
At risk	12.5–13.4 cm
Moderate malnutrition	11.5–12.4 cm
Severe malnutrition	<11.5 cm
Developmental Milestones
Social smile	1.5 months
Head control	4 months
Sits unsupported	7 months
Crawls	10 months
Stands unsupported	10–12 months
Walks	12–13 months
Talks	18 months
CSF WBC (/mm³)
Term newborn	0–25
>2 weeks	0–5

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