Nota Perubatan

Haemoglobin (Hb) Cutoffs

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Haemoglobin cutoffs to define anaemia in individuals and populations

📌 Children

  • 6 – 23 months: Hb <10.5 g/dL
  • 24–59 months: <11.0 g/dL
  • 5 – 11 years: <11.5 g/dL
  • 12–14 years, nonpregnant girls: <12.0 g/dL
  • 12–14 years, boys: <12.0 g/dL

📌 Adults

  • 15–65 years, nonpregnant women: <12.0 g/dL
  • 15–65 years, men: <13.0 g/dL

📌 Pregnancy

  • First trimester: <11.0 g/dL
  • Second trimester: <10.5 g/dL
  • Third trimester: <11.0 g/dL

Haemoglobin cutoffs for severity of anaemia

Population Normal (g/dL) Mild anaemia (g/dL) Moderate anaemia (g/dL) Severe anaemia (g/dL)
Children
6 – 23 months ≥10.5 9.5–10.4 7.0–9.4 <7.0
24–59 months ≥11.0 10.0–10.9 7.0–9.9 <7.0
5–11 years ≥11.5 11.0–11.4 8.0–10.9 <8.0
12–14 years, non-pregnant girls ≥12.0 11.0–11.9 8.0–10.9 <8.0
12–14 years, boys ≥12.0 11.0–11.9 8.0–10.9 <8.0
Adults
15–65 years, non-pregnant women ≥12.0 11.0–11.9 8.0–10.9 <8.0
15–65 years, men ≥13.0 11.0–12.9 8.0–10.9 <8.0
Pregnant
First trimester ≥11.0 10.0–10.9 7.0–9.9 <7.0
Second trimester ≥10.5 9.5–10.4 7.0–9.4 <7.0
Third trimester ≥11.0 10.0–10.9 7.0–9.9 <7.0
No matches found.

Haemodilution in pregnancy

  • Maternal physiological adaptation to pregnancy: plasma volume expansion exceeds the increase in red blood cell mass, resulting in functional hemodilution. There is a drop in the concentration of red blood cells, hemoglobin, and hematocrit.
  • Hemodilution is most pronounced during second trimester. Hence, WHO sets a lower hemoglobin threshold for second trimester compared to the first and third.
  • In third trimester, plasma volume continues to increase, but at a slower rate. The discrepancy between plasma and RBC mass narrows, and hemoglobin levels stabilize

Reference

  1. WHO Guideline on haemoglobin cutoffs to define anaemia in individuals and populations https://www.who.int/publications/i/item/9789240088542

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