The body's blood filter and immune system

Spleen

The spleen is an important organ in the lymphatic system that filters the blood, breaks down old blood cells, and strengthens the immune system. It also acts as a blood reserve and plays a central role in infections and bleeding.

Quick version

What is the spleen?

The spleen is an organ in the body's lymphatic system that plays an important role in the immune system and blood composition. It acts as a filter for the blood and helps the body fight infections and break down old or damaged blood cells. The spleen also stores blood and acts as a reserve in case of bleeding.

Anatomy and location

The spleen is located in the upper left part of the abdomen, just below the diaphragm and behind the stomach. It is approximately 10–12 cm long in adults, weighs about 150 grams and is surrounded by a protective capsule

Functions of the spleen

The spleen has several central functions:

  • Filtration of blood: Removes old red blood cells and platelets and recycles iron and other components.
  • Immune defense: Produces and stores white blood cells (lymphocytes) and antibodies that help the body fight infections.
  • Blood reserve: Can store red blood cells and platelets that can be quickly released in the event of bleeding or increased need for oxygen transport.

Importance for the immune system

Because the spleen participates in recognizing and neutralizing bacteria, viruses and other foreign substances, it is a central part of the body's defense against infections. People who lack a spleen (due to illness or surgery) are at increased risk of certain bacterial infections.

Common diseases and conditions

The spleen can be affected by several different diseases and conditions, such as:

  • Splenomegaly (enlarged spleen) in infections, blood diseases, or liver disease
  • Splenic rupture (rupture) after trauma to the abdomen
  • Blood diseases that affect the breakdown of blood cells, e.g. hemolytic anemia
  • Infections such as mononucleosis ("glandular fever") can temporarily enlarge the spleen

Relevant symptoms

  • Pressure or pain under the left rib cage
  • Fatigue or anemia (anemia)
  • Increased bleeding tendency
  • Recurrent infections
  • Enlarged abdomen with severe splenomegaly

Related conditions and diagnoses

  • Splenomegaly (enlarged spleen)
  • Splenic rupture
  • Hemolytic anemia
  • Mononucleosis
  • Hypersplenism (overactive spleen)

Written by: The team at Testmottagningen.se
Reviewed by:Hannah Krantz, leg. läkare

Tests related to Spleen

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MRI Full Body

MRI Full Body

Magnetic resonance imaging
  • Magnetic camera examination of the full body
  • Recommended for those who are healthy for screening purposes
  • Detailed examination with magnetic camera
  • MRI full body, referral sent directly

19 995 kr

SAVE 400 kr
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MRI Abdomen/MRCP
  • Abdominal MRI visualizes the liver, kidneys, bile ducts, and pancreas.
  • Recommended for abdominal pain or suspected abnormalities.
  • MRCP shows bile and pancreatic ducts – without contrast agents.
  • Radiation-free exam with referral and specialist report included.

6 995 kr6 595 kr

SAVE 500 kr
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MRI Full body Plus
  • Radiation-free whole-body MRI examination.
  • 50+ blood tests for an extended medical overview.
  • Early detection of risks and diseases.

21 000 kr20 500 kr

SAVE 995 kr
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MRI Full Body Pro
  • Full body MRI scan.
  • 70+ blood tests incl. biological age.
  • Long-term ECG 5–7 days with ePatch.

24 995 kr24 000 kr

Call included
Ultrasound Spleen
  • Ultrasound of the spleen shows size, blood flow and changes such as cysts or enlargement.
  • Recommended for pain under the ribs, infections or suspected splenomegaly.
  • Quick, painless and radiation-free examination of the structure and function of the spleen.
  • Written opinion and recommendation from a specialist doctor are included.

2 495 kr