Red Blood Cell Survival Study – Why am I having this test?

A red blood cell survival study can be used to help identify the cause of anemia and identify any sites in the body where red blood cells (RBCs) are being destroyed. Anemia is a condition in which you do not have enough red blood cells or hemoglobin, which is a substance in red blood cells that carries oxygen.

What is being tested?

This test measures how long your RBCs survive. To do this, some of your RBCs are removed and tagged with a harmless radioactive material called chromium-51. The RBCs are then injected back into you. Blood samples are later taken to see how long these tagged RBCs survive.

Scans can also be done on your spleen and liver and on the sac that surrounds your heart (pericardial sac). These tests show any abnormal activity in any of these areas, or they show if RBCs are being destroyed.

What kind of sample is taken?

A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel. Your health care provider will collect blood samples at several intervals:

• 30 minutes after the blood–chromium-51 solution is injected into your body.
• 24 hours after the blood–chromium-51 solution is injected into your body.
• Every 1–3 days for 4 weeks after the initial injection.

How are the results reported?

Your test results will be reported as values that represent how long the tagged RBCs survive. Your health care provider will compare your results to normal ranges that were established after testing a large group of people (reference ranges). Reference ranges may vary among labs and hospitals. For this test, common reference ranges are:

• Plasma radioactivity half-life: 0–2 hours.
• Tagged chromium-51 red blood cell half-life: 25–35 days.
• Gamma scan: only slight spleen, liver, and bone marrow radioactivity.

What do the results mean?

Increased chromium-51 half-life may indicate:

• Thalassemia minor, which is an inherited blood disorder.

Decreased chromium-51 half-life may indicate:

• Various types of anemia.
• Leukemia.
• Certain blood disorders in which RBCs are destroyed in excess.

Talk with your health care provider about what your results mean.

Questions to ask your health care provider

Ask your health care provider, or the department that is doing the test:

• When will my results be ready?
• How will I get my results?
• What are my treatment options?
• What other tests do I need?
• What are my next steps?

Summary

• A red blood cell (RBC) survival study can be used to help identify the cause of anemia and identify any sites where RBCs are being destroyed.
• This test measures how long your RBCs survive.
• To do this, some of your RBCs are removed and tagged with a harmless radioactive material. The RBCs are then injected back into you. Blood samples are later taken to see how long these tagged RBCs survive.