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Chapter 3: Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50–D89)

Anaemias and other disorders of the red cells, white cells and platelets, clotting problems such as haemophilia, and conditions involving the immune mechanism, including immune deficiency.

Chapter 3 spans codes D50–D89 in the FY2027 ICD-10-CM tabular list. This guide explains 13 of its most common codes — select a code for its official description, a plain-English explanation and a note on when the code is used.

ICD-10 Chapter 3: Blood & Immune Disorders — illustrative image

Codes in this chapter

CodeOfficial descriptionIn plain words
D50.9Iron deficiency anemia, unspecifiedIron deficiency anaemia: too few red blood cells because the body lacks iron, needed to make haemoglobin.
D51.9Vitamin B12 deficiency anemia, unspecifiedAnaemia caused by lack of vitamin B12, which is needed to make healthy red blood cells and nerves.
D57.1Sickle-cell disease without crisisSickle cell disease is an inherited condition in which red blood cells become stiff and sickle-shaped, blocking small vessels.
D62Acute posthemorrhagic anemiaAnaemia that develops quickly after significant bleeding, for example after surgery, injury or gastrointestinal haemorrhage.
D63.1Anemia in chronic kidney diseaseAnaemia that occurs as a complication of chronic kidney disease, mainly because failing kidneys make less erythropoietin.
D63.8Anemia in other chronic diseases classified elsewhereAnaemia that develops in the setting of another long-term (chronic) disease, such as inflammation or cancer.
D64.9Anemia, unspecifiedAnaemia means a low level of haemoglobin or red blood cells, reducing the blood's oxygen-carrying capacity.
D66Hereditary factor VIII deficiencyHaemophilia A is an inherited bleeding disorder caused by deficiency of clotting factor VIII.
D68.51Activated protein C resistanceActivated protein C resistance, usually due to the factor V Leiden variant, makes blood more likely to clot.
D69.6Thrombocytopenia, unspecifiedThrombocytopenia is a low platelet count, which can increase bruising and bleeding.
D72.829Elevated white blood cell count, unspecifiedA higher-than-normal white blood cell count, often seen with infection or inflammation.
D75.839Thrombocytosis, unspecifiedThrombocytosis is a higher-than-normal platelet count in the blood.
D86.9Sarcoidosis, unspecifiedSarcoidosis is an inflammatory condition in which clusters of immune cells (granulomas) form, most often in the lungs and lymph nodes.

This guide explains ICD-10-CM codes in plain language for patients, students and other readers. It is educational information only — not coding, billing or medical advice. The code recorded for any real encounter is assigned from the full clinical documentation by the treating team and qualified coders, and only they can decide which code fits a specific case.

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