Red Cell Mass and Plasma Volume Measurement
What is a Red Cell Mass and Plasma Volume Measurement?
This test is carried out to measure the amount of red cells and plasma your blood contains. It is normally not carried out within four weeks of bloodletting.
What is involved?
A small injection with a special radioactive (Iodine-125) tracer will
be injected into a vein, usually in your arm. The injection is no more
painful than a blood test.
Following this injection we will need to take a blood sample from a vein,
again usually in your arm. This blood samples will be used for measuring
the plasma volume.
To measure the red cell mass we will need to take a blood sample which will be used to label some red cells with a radioactive material (Chromium-51). The labelled red cells will be re-injected via a vein in your arm.
After a short delay we will need to take a blood sample in order to measure the red cell mass in your blood.
You may leave the department between each part of the procedure. But you must attend for the re-injection of blood at the times given to you by the technician or radiographer.
You can eat and drink normally. You will be free to go when the technician or radiographer is satisfied that the required information is sufficient.
How long will it take?
The whole test takes about two hours, but you may be free to leave the department between the different parts of the procedure.
Do I need to do anything before and after the test?
Before the test you may eat and drink normally.
After the test you do not need to take any precautions and can eat and
drink normally.
Is the radiation dangerous?
The amount of radiation you receive is small. It is comparable to that of an X-ray examination. The substances we inject are non-toxic and will not make you feel sick or drowsy.
What about pregnancy?
The amount of radioactivity we use for this test is so low that there is no risk to any unborn child.
What about breastfeeding?
Radioactive substances can come out in breast milk. Please phone the Nuclear Medicine Department before your test if you are breastfeeding, so that we can advise you if you need to stop feeding for a length of time.
Can I bring a friend or relative with me?
A friend or relative can attend with you but they will not be able to accompany you for the injection or when we take the blood samples.
Can I still look after children and pets?
You do not have to take any special precautions when dealing with small children or pets after this procedure. The radiation from your body is so small that it will not affect anybody near you.
Can I return to work after my test?
Yes, there is usually no problem.
What about my result?
As the blood samples will be analysed at a later time we are unable to tell you the results of the test. The results will be sent to the doctor who requested the test.
If you have any further questions after reading this information
please contact:
The Nuclear Medicine Department (01202) 442499
References
This information has been produced by:
Head of Nuclear Medicine: Lars Jansson
Date Produced: February 2007
Review Date: February 2008
Responsible Clinician: Dr NK Robson, Consultant Radiologist
