Question 1

How do I investigate iron deficiency anaemia in primary care?

Accepted Answer

Start with iron studies: ferritin (<30 ng/mL is diagnostic), serum iron, TIBC, and transferrin saturation. In all men and post-menopausal women — and pre-menopausal women without an obvious cause — endoscopic GI investigation is required to exclude malignancy. Coeliac screen and H. pylori testing should also be considered.

Question 2

When should a GP suspect haematological malignancy?

Accepted Answer

NICE 2WW criteria include unexplained lymphadenopathy >1 cm persisting more than 6 weeks, unexplained splenomegaly, B symptoms (drenching night sweats, unintentional weight loss, fever), or unexplained cytopenias. Blast cells on blood film require same-day emergency haematology referral.

Question 3

How do I manage a supratherapeutic INR on warfarin?

Accepted Answer

INR 3.1–5 with no bleeding: reduce or omit next dose. INR 5–8 with no bleeding: hold 1–2 doses and consider 1–2 mg oral Vitamin K. INR >8 or any major bleeding: administer IV Vitamin K 5–10 mg plus 4-factor PCC (Beriplex) for life-threatening haemorrhage, and admit urgently.

Question 4

What are the CRAB criteria for multiple myeloma?

Accepted Answer

CRAB criteria define myeloma end-organ damage: Calcium >2.75 mmol/L, Renal impairment (creatinine >177 µmol/L or eGFR <40), Anaemia (Hb <100 g/L), Bone lesions (lytic lesions on imaging). Any single CRAB feature with a monoclonal paraprotein warrants urgent haematology referral for myeloma workup.

Question 5

Which DOAC is first-line for non-valvular atrial fibrillation?

Accepted Answer

Apixaban is most commonly used as first-line due to its favourable bleeding profile demonstrated in the ARISTOTLE trial. Rivaroxaban, edoxaban, and dabigatran are alternatives. DOACs are preferred over warfarin for non-valvular AF. Renal function and CrCl must be checked before prescribing and annually thereafter.

Question 6

What is the CHA₂DS₂-VASc threshold for anticoagulation?

Accepted Answer

NICE recommends anticoagulation for men with CHA₂DS₂-VASc ≥2 and women with score ≥3. Men with score 1 and women with score 2 should have anticoagulation considered. A score of 0 in men or 1 in women (female sex only) does not require anticoagulation.

Parameter	Male Reference	Female Reference	Clinical Note
Haemoglobin (Hb)	130–180 g/L	115–165 g/L	Anaemia: Hb <130 (M) / <115 (F)
Haematocrit (Hct)	0.40–0.54	0.36–0.48	Polycythaemia if elevated
MCV (Mean Cell Volume)	80–100 fL	80–100 fL	Microcytic <80 / Macrocytic >100
MCH	27–33 pg	27–33 pg	Low in IDA; high in B12/folate deficiency
MCHC	315–360 g/L	315–360 g/L	Elevated in hereditary spherocytosis
RDW (Red Cell Distribution Width)	<14.5%	<14.5%	Elevated in IDA, mixed deficiency
White Cell Count (WBC)	4.0–11.0 ×10⁹/L	4.0–11.0 ×10⁹/L	Leukocytosis >11 / Leukopenia <4
Neutrophils	1.8–7.5 ×10⁹/L	1.8–7.5 ×10⁹/L	Neutropenia <1.5; Severe <0.5 (agranulocytosis)
Lymphocytes	1.5–4.5 ×10⁹/L	1.5–4.5 ×10⁹/L	Lymphocytosis: EBV, CLL. Lymphopenia: steroids, HIV
Eosinophils	0.04–0.4 ×10⁹/L	0.04–0.4 ×10⁹/L	>0.5 = eosinophilia: parasites, asthma, drugs, Addison's
Platelets	150–400 ×10⁹/L	150–400 ×10⁹/L	Thrombocytopenia <150; Critical <20
Reticulocytes	25–100 ×10⁹/L	25–100 ×10⁹/L	Elevated in haemolysis/haemorrhage. Low in marrow failure

Haematology

Haematology in General Practice — Key Messages

Full Blood Count — Normal Ranges & Clinical Significance