Haemoglobin
Lowered haemoglobin during normal pregnancy is a physiological finding.
What our notes say
- Lowered haemoglobin during normal pregnancy is a physiological finding. (Junior Clerkship in Reproductive Health (MBOG 4200): end of year examination, 4 )
- D is also a rhesus-type feature (the haemoglobin is usually normal at birth in ABO disease), so the question is loosely worded. (Paediatrics end of first trimester exam (MBPE 4300): 27 November 2018, 49 of 50 )
- Haemoglobin and group and crossmatch to guide transfusion. (Reproductive Health 1 End of Trimester CAT: ectopic pregnancy, ANC and abortion )
- Laboratory tests: haemoglobin, blood group and Rhesus, HIV, VDRL or syphilis, urinalysis, malaria and hepatitis B where indicated. (Reproductive Health 1 End of Trimester CAT: ectopic pregnancy, ANC and abortion )
- Haemoglobin and full blood count, random blood glucose, urea, electrolytes and creatinine, liver function, blood group and cross-match, and a HIV test. (Junior Clerkship in Reproductive Health (MBOG 4200): end of year examination, 4 )
- Full blood count: baseline haemoglobin and platelets (haemoglobin may be normal early). (General Surgery CAT 2 (MBSG 4600): 4 October 2021)
Study material on Haemoglobin
- Internal Medicine End of Semester CAT (MBChB 4): haematology and renal, 30 MCQs and 3 short answers
- Chemical Pathology MCQs: Diabetes, Renal & Liver Disease
- Haematology paper 1 Past Papers
- Approach to anaemia
- Physiological changes in pregnancy
- cat 2 2014 — Source Paper Awaiting Edit
- hsd haematology
- Year 3: Haematology and Blood Transfusion Pathology
- Pathology Spot Exam Revision: Lymphoma, Adenoma, Appendicitis, FISH
- EXAM: Spot/Practical Examination
Practice questions on Haemoglobin
A 28-year-old woman presents with fatigue and pallor. Complete blood count shows low haemoglobin level and peripheral blood film shows microcytic hypochromic red blood cells. What is the most likely diagnosis?
- Aplastic anaemia
- Haemolytic anaemia
- Iron deficiency anaemia
- Vitamin B12 deficiency
Answer: C. Microcytic hypochromic red cells reflect impaired haemoglobin synthesis, classically caused by iron deficiency. Vitamin B12 deficiency instead causes macrocytic anaemia; the other options don't typically present with this cell morphology. ---
Which haemoglobin is predominant in a normal adult?
- HbF
- HbA2
- HbA
- HbH
Answer: C. HbA (α2β2) constitutes approximately 96–98% of adult haemoglobin; HbA2 is ~2.5% and HbF <1%. ---
A patient experiences an unexpected drop in haemoglobin and mild jaundice approximately 7 days after receiving a blood transfusion. A direct antiglobulin test (DAT) is positive. Which blood group system is most notoriously associated with this type of reaction?
- The ABO blood group system due to common pre-formed IgM antibodies.
- The Rh blood group system, often involving anti-D following Rh-positive exposure.
- The Duffy blood group system, known for its association with malaria resistance.
- The Kidd blood group system, notorious for causing anamnestic antibody responses.
Answer: D. The timing (3-10 days post-transfusion), fall in Hb, mild jaundice, and positive DAT are consistent with a delayed haemolytic transfusion reaction (DHTR). DHTRs occur when low-level alloantibodies, often not detected on initial antibody screens, are boosted by the transfused RBCs, leading to an anamnestic immune response. The Kidd blood group system is particularly notorious for causing these types of reactions, as K
At what haemoglobin threshold does the NICE guideline recommend considering red cell transfusion in a stable non-bleeding adult?
- Hb <10 g/dL
- Hb <8 g/dL
- Hb <7 g/dL
- Hb <6 g/dL
- Hb <9 g/dL ✅ Answer: C
Answer: A. NICE guidelines generally recommend considering red cell transfusion for stable, non-bleeding adults when haemoglobin levels fall below 7 g/dL.
A 28-year-old woman presents with fatigue and pallor. Complete blood count shows low haemoglobin level and peripheral blood film shows microcytic hypochromic red blood cells. What is the most likely diagnosis?
- Vitamin B12 deficiency
- Iron deficiency anaemia
- Aplastic anaemia
- Haemolytic anaemia
Answer: B. Microcytic hypochromic red cells are the classic morphological pattern of iron deficiency anaemia, reflecting impaired haemoglobin synthesis. ---
Test to detect haemoglobin S (sickle cell trait)?
- Coombs' test
- Osmotic fragility test
- Metabisulfite test
- Schilling test
Answer: C. Sodium metabisulfite deoxygenates blood, inducing sickling of HbS-containing cells — a simple screening test. ---