Haemoglobin is an iron-containing protein in the red blood cells that gives them their colour. It circulates in the bloodstream, carrying oxygen from the lungs to the rest of the body. Image used for representational purposes only
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Platelets are blood cells essential for blood clotting, while haemoglobin is the iron-containing molecule that helps carry oxygen. Platelets are small, colourless cells normally found in your child’s bloodstream. They spring into action when there is an injury to blood vessels, helping to stop bleeding and forming clots. Haemoglobin, on the other hand, is an iron-containing protein in the red blood cells that gives them their colour. It circulates in the bloodstream, carrying oxygen from the lungs to the rest of the body.
The normal range of platelets and haemoglobin in blood varies with age, and can also fluctuate slightly from day to day. A normal platelet count for children is generally between 1,50,000 and 4,50,000 platelets per microliter of blood. Normal haemoglobin (HGB) levels in children vary significantly by age. Newborns have the highest levels, but these gradually decrease in the first months of life before stabilising with minor variations until puberty.
Haemoglobin levels
Low haemoglobin levels cause a condition known as anaemia and reduce the amount of oxygen delivered to tissues. Common symptoms include unusual tiredness, weakness, and reduced activity levels. Causes of anaemia include nutritional deficiencies (iron, vitamin B12, folic acid), chronic diseases such as liver or kidney disorders, blood loss, and genetic mutations affecting the haemoglobin.
High haemoglobin levels cause a condition called polycythaemia, which can also be harmful. This condition may be asymptomatic or may cause symptoms such as headaches, fatigue, dizziness, blurred vision, itchy skin (especially after warm baths), facial redness, or an enlarged spleen leading to discomfort in the upper left abdomen. Other signs include numbness or tingling in the extremities, bone pain, nosebleeds, shortness of breath, or even blood clots, such as deep vein thrombosis or stroke. Common causes include heart and lung disease or a genetic condition called Polycythaemia Vera.
Platelet levels
A low platelet count, known as thrombocytopenia, can become life-threatening if the platelet level drops below a critical range, as internal bleeding may occur. Symptoms include easy bruising, frequent nosebleeds, or small red/purple dots (petechiae) on the skin. Causes include viral infections (such as dengue), certain medications, autoimmune conditions, and blood cancers such as leukaemia. If you notice reddish spots or excessive bruising in your child, consult a paediatrician immediately.
A high platelet count, known as thrombocytosis, usually results from an underlying condition. It often has no symptoms and is detected incidentally during routine health checks. The most common cause in children is recovery from a recent viral infection, which typically resolves within a few weeks. Other causes include infections, inflammation, or iron-deficiency anaemia.
If your child has nosebleeds, frequent bruising, persistent headaches, fatigue, lethargy, or blood in the stool or urine, consult your paediatrician. A doctor can interpret a complete blood count (CBC) to identify the cause of abnormalities and decide whether further tests or treatment are necessary.
(Dr. Suja Ramanathan is chief of laboratory (Tamil Nadu), Hitech Metropolis Healthcare Ltd. suja.ramanathan@hitechlabsindia.in)
Published – September 28, 2025 04:00 pm IST