Know your Hb
The health of your blood contributes to the health of all other organs and should be optimised whenever possible.
1. What Does “Hb” Refer To?
Hb stands for haemoglobin, an iron-containing protein in red blood cells that gives blood its red colour. It carries oxygen from the lungs to tissues and carbon dioxide back to the lungs.
A low Hb level is referred to as anaemia. Hb levels vary by age, gender, and altitude.
2. WHO Hb Thresholds
- Adult males: Hb ≥ 13 g/dL
- Adult females: Hb ≥ 12 g/dL
- Preoperative (anticipated blood loss >500 mL): Hb ≥ 13 g/dL
- Pregnancy:
- First trimester: Hb > 11 g/dL
- Second trimester: Hb > 10.5 g/dL
- Postpartum: Hb > 10 g/dL
3. Why Has WHO Declared Anaemia a Public Health Issue?
Anaemia affects up to a third of the global population, predominantly women. The most common cause is iron deficiency.
South African survey findings:
- 1 in 5 adults affected
- 22–44% of women aged 12–49
- 43.7% of pregnant women
- 10.7% of children under 5
- 50% of patients scheduled for non-urgent surgery
Impact of Low Hb
- General Effects:
- Cognitive dysfunction
- Fatigue
- Headaches
- Emotional instability
- Depression
- Restless leg syndrome
- Cardiac Patients:
- Increased morbidity and mortality in heart failure and cardiac surgery
- Pregnancy:
- Reduced physical activity and immunity
- Increased risk of maternal and infant mortality
- Neurocognitive alterations in the baby
- Children & Adolescents:
- Impaired brain function and concentration
- Hospitalised Patients:
- Higher death rates
- Increased infections, kidney injury, stroke, heart attacks
- Longer hospital and ICU stays
- Risk of inappropriate transfusion
- People Living with HIV:
- Anaemia increases mortality risk
- 72% of South Africans with HIV are anaemic
4. Managing Low Hb / Anaemia
A thorough history, examination, and lab tests are essential to:
- Assess impact on heart and other conditions
- Identify the cause for targeted treatment
Key history points:
- Symptoms: fatigue, irritability, headache, palpitations
- Diet: vegetarianism, tea/coffee intake, cereal consumption
- Medications: metformin, NSAIDs, antacids, PPIs, traditional remedies
- Bleeding tendencies
- Blood donation history
- Family history of blood disorders or GI cancers
- GI bleeding: ulcers, haemorrhoids
- Past gastric surgery
- Chronic diseases: kidney, heart, liver
- Obstetric history: pregnancies, bleeding, iron supplementation
Treatment includes:
- Iron replacement
- Addressing the cause (e.g., poor diet, blood loss)
5. Iron Matters
Iron is essential for:
- Hb production (⅔ of body iron is in red cells)
- Energy production
- Nervous system health
Iron deficiency can occur with or without anaemia and progresses in stages. Anaemia is a late sign.
Symptoms to watch for (even without low Hb):
- Pallor
- Fatigue
- Restless leg syndrome
- Pica (craving non-food items)
- Exercise intolerance
- Shortness of breath
- Weakness
- Hair loss
- Depression, anxiety
- Frequent infections
- Palpitations
- Sleepiness
- Difficulty concentrating
- Angina
- Oedema
- Headaches
Pregnancy Note:
Iron deficiency during pregnancy can cause irreversible brain changes in the baby, affecting long-term development and behaviour.
6. Role of Transfusion in Treating Low Hb
A blood transfusion is like a liquid organ transplant and carries risks per unit transfused. It should not be used as a quick fix.
Transfusion decisions must consider:
- Cause and severity of anaemia
- Impact on heart and other conditions
- Discussion of risks, benefits, and alternatives with the patient
- Transfuse one unit at a time and assess response
Take-Home Message
Maintaining and optimising blood health improves quality of life, productivity, and reduces healthcare costs.
Know Your Hb
- Check your iron profiles
- Monitor symptoms
- Access your results via the Ampath App