Health Topic

Blood Disorders

Blood disorders affect one or more parts of the blood and prevent your blood from doing its job. Find out about the types, causes, and treatments.

Reviewed Reviewed by a registered pharmacistGeneral information

Also called: Hematologic diseases

Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Blood Disorders

Your blood is living tissue made up of liquid and solids. The liquid part, called plasma, is made of water, salts and protein. Over half of your blood is plasma. The solid part of your blood contains red blood cells, white blood cells and platelets.

Blood disorders affect one or more parts of the blood and prevent your blood from doing its job. They can be acute or chronic. Many blood disorders are inherited. Other causes include other diseases, side effects of medicines, and a lack of certain nutrients in your diet.

Types of blood disorders include:

  • Platelet disorders, excessive clotting, and bleeding problems, which affect how your blood clots
  • Anemia, which happens when your blood does not carry enough oxygen to the rest of your body
  • Cancers of the blood, such as leukemia and myeloma
  • Eosinophilic disorders, which are problems with one type of white blood cell.

It sits within Blood, Heart and Circulation.

The lead U.S. institute for this subject is the National Heart, Lung, and Blood Institute.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Blood Disorders

42,548 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

Start Here

  • Blood DiseasesNational Institute of Diabetes and Digestive and Kidney Diseases

Symptoms

Diagnosis and Tests

Related Issues

Genetics

Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Hematologic Diseases. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Blood Disorders, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.