Child's blood characteristics

2021-01-30 12:00 AM

Although hematopoiesis in children is strong, but not stable. Many cases of the disease easily affect the hematopoiesis, so the child is prone to anaemia, but the child's recovery is also very fast.

Features of hematopoiesis in children

Blood production in the fetus

With the formation and development of the fetus, hematopoietic system organs are gradually formed and differentiated from the middle tissue of the embryo. Hematopoiesis begins very early, in the third week of embryonic period and is performed in several parts:


Hepatic hematopoiesis at 5 weeks of embryo. The liver is the main blood-forming place in the middle of the fetus, then weakens, and stops completely when the baby is born. The liver produces all types of blood cells, but mainly red blood cells.

Bone marrow:

Bone marrow is formed in the 6th week of embryonic period, but it is not after the 4th - 5th month of the fetal period, when the hematopoiesis in the liver weakens, the blood production in the bone marrow gradually strengthens. time to give birth.

Spleen, lymph nodes:

Spleen begins to participate in hematopoiesis from 3 to 4 months of fetal period, spleen produces mainly lymphocytes and part of red blood cells.

Lymph nodes and a part of thymus gland are also involved in hematopoiesis in 5-6 months of fetal period.

Postpartum hematopoiesis

After birth, the bone marrow is the primary organ that produces major blood cells.

In young children, all the bone marrow produces blood cells.

In children and adults, blood production is mainly in flat bones such as the ribs, sternum, skull, scapula, collarbone, spine and part of the long bone.

Although hematopoiesis in children is strong, but not stable. Many causes of the disease easily affect the hematopoiesis, so the child is susceptible to anemia, but the child's recovery ability is also very fast. The lymph node system in children is also susceptible to a reaction to the underlying causes.

When suffering from anemia, the blood-forming organs are also prone to proliferation and dysplasia. Therefore, in clinical appearance, liver, spleen, lymphadenopathy, and blood tests show that there is a dysplasia of this organization, creating blood cells like in the fetal period.

Peripheral blood characteristics

Gaping bridge

A number of bridge holes:

Newborn babies have a very high number of bridges: 4.5 - 6.0 X 1012 / L.

Day 2 - 3 after delivery, the number of fissures decreased rapidly due to some broken bridges, so the clinical phenomenon of physiological jaundice.

By the end of the neonatal period, the number of bridge holes is about 4.0 - 4.5 X 1012 / L.

In children under 1 year old, especially children aged 6-12 months, the number of bridge holes decreased to about 3.2 - 3.5 X 1012 / L. At this stage, the child grows rapidly, the need for hematopoiesis is high, but it is susceptible to the deficiency of some hematopoietic factors such as iron and therefore the hematopoiesis is not met, so this phenomenon is called physiological anaemia.

Children over 1-year-old have a gap number of about 4.0 X 1012 / L.

Mesh bridge:

Reticulocytotic in peripheral blood: 0.5 - 2%.

Malnutrition principle: term infants: 1-4%. Premature infants: 3 - 6%.


Amount of hemoglobin (Hb): Newborn: 170 - 190 g / l. Children <1 year: 100 - 120 g / l. Children> 1 year: 130 - 140 g / L      

Haemoglobin composition:

Infants: HbF: 80 - 60%, HbA1: 20 - 40%. HbA2: 0.03 - 0.6%

Children 6 months: HbF: 1-5%. HbA1: 93 - 97%. HbA2: 2- 3%

Children> 1 year: HbF: <1%. HbA1: 97 - 98%. HbA2: 2- 3%.

At this time, the child has a phenomenon of iron deficiency due to iron reserve during the period when the fetus has used up and the child's ability to absorb iron at this time is poor so the amount of haemoglobin decreases.

White blood cells

WBC count:

The number of leukocytes changes with age, the younger the child the higher the number of leukocytes.

Newborn: 10,000 - 30,000 / mm3 (10 - 30 X 109 / L).

Children <1 year old: 10,000 - 12,000 / mm3 (10 - 12 X 109 / L).

Children> 1 year old: 6,000 - 8,000 / mm3 (6 - 8 X 109 / L).

Leukocyte formula: changes gradually with age.


Newborns: In the first hours after birth: 65%. Day 5 - 7: 45%.

Children 9 - 10 months: 30%.

Children 5 - 7 years old: 45%.

14 years old: 65%.


Newborns: In the first hours after birth: 20-30%. Days 5-7: 45%.

Children 9 - 10 months: 60%.

Children 5 - 7 years old: 45%.

Children 14 years: 30%.

Leukocytes like acid: 2%.

Monocytes: 6-9%.

Alkaline leukocytes: 0.1 - 1%.


Platelet count is less variable.

Infant: 100,000 / mm3 (100 X 109 / L)

Outside infant age: 150,000 - 300,000 / mm3 (150 - 300 X 109 / L)

A few other features

Circulating blood volume

Compared with bodyweight, circulating blood volume in children is more than that of adults. Circulating blood volume in:

Newborn: 14% of body weight.

Children <1 year: 11% of body weight.

Older children: 7 - 8% of body weight.

Prothrombin complex (Prothrombin ratio)

Newborns: 65 ± 20%, lowest on day 3 - 4, after the gradual increase, normal on day 10.

Other Ages: 80 - 100%.