Doctors prescribe a Hemoglobin test in the following situations:
Diagnosing anaemia in patients presenting with fatigue, weakness, pallor, shortness of breath, dizziness, and reduced exercise tolerance where a low hemoglobin confirms oxygen-carrying deficiency and guides the investigation of its underlying cause.
Antenatal screening in all pregnant women where hemoglobin is monitored at every trimester as iron requirements increase significantly during pregnancy and anaemia is associated with adverse outcomes including preterm birth, low birth weight, and maternal complications.
Pre-operative assessment before elective or emergency surgery where baseline hemoglobin determines fitness for anaesthesia and surgery, guides pre-operative blood transfusion decisions, and establishes the threshold for intraoperative blood loss tolerance.
Monitoring treatment response in patients receiving iron supplementation, Vitamin B12 injections, folate therapy, or erythropoietin for anaemia, where serial hemoglobin measurements confirm that levels are rising adequately with treatment.
Evaluating patients with chronic diseases including chronic kidney disease, rheumatoid arthritis, inflammatory bowel disease, and malignancy where anaemia of chronic disease is a common complication requiring regular hemoglobin monitoring and targeted management.
Investigating polycythaemia in patients with an abnormally high hemoglobin where elevated levels may indicate dehydration, high altitude adaptation, chronic lung disease, or a myeloproliferative disorder such as polycythaemia vera requiring haematological evaluation.
Routine preventive health screening as part of a complete blood count in annual health checkups, particularly in women of reproductive age, vegetarians, elderly individuals, and children where anaemia risk is highest.