Notes as read in an Online Booklet titled, "Understanding Myeloma" published online by Leukaemia Foundation

Below Text is kind courtesy: Leukemia Foundation. 

I am sharing the same here with due credit purely for educational purposes and to help you, the reader, understand the theory behind all the Tests and Diagnostic symptoms outlined in my previous post

“Myeloma, also known as multiple myeloma, is a cancer of plasma cells (mature B-lymphocytes) that usually arises in the bone marrow. Myeloma develops when plasma cells undergo a cancerous, or malignant change and become myeloma cells. These myeloma cells multiply without any proper order, forming collections known as tumours that accumulate in different parts of the body, especially in the bone marrow and on the surfaces of different bones in the body. These tumours secrete chemicals that stimulate other bone marrow cells (osteoclasts) to remove calcium from the bone. As a result bones can become weaker, more brittle and break more easily.

Under normal conditions, plasma cells produce immunoglobulins or antibodies that help protect the body from infection and disease. Myeloma cells produce an abnormal type of immunoglobulin called paraprotein, (also known as monoclonal immunoglobulin, myeloma protein, or simply M protein). This can be detected in the blood. Sometimes excessive amounts of fragments of immunoglobulin known as light chains are produced. These light chains can be detected in the blood and they also appear in the urine. Light chains detected in the urine are called Bence-Jones protein. Some light chains can cause kidney damage.

As myeloma cells multiply, they crowd the bone marrow and prevent it from making normal numbers of red cells, white cells and platelets. Myeloma cells can also interfere with the production of normal antibodies. This can make people with myeloma anaemic, more susceptible to infections and to bleeding and bruising more easily.

Myeloma is diagnosed using information gathered from a number of different tests. These include a physical examination, blood tests, urine tests, a bone marrow biopsy, x-rays and other more specialised bone imaging tests.

A diagnosis of myeloma is only made when there is evidence that organ damage has occurred as a result of the disease. This damage is summarised by the acronym CRAB:

C – hypercalcaemia

R – renal impairment

A – anaemia or bone marrow failure

B – bone disease

BLOOD AND URINE TESTS TO DIAGNOSE MYELOMA

Serum protein and serum electrophoresis are tests carried out to measure the amount and type of paraprotein in your blood. These are simple tests that require a sample of your blood, which is usually taken from a small vein in your arm or hand.

Parts of the paraprotein known as ‘light chains’ or Bence Jones protein may be filtered out of the blood in the kidneys and passed in the urine. Urine electrophoresis is a test used to measure the amount of protein in the urine. You may be asked to collect all of the urine you pass in a 22-hour period so that the amount of light chains you are passing during this period can be measured. This simply involves collecting all the urine you pass during this period into a large container and returning it to the hospital the following day. Your doctor or nurse will supply you with a suitable container for this collection.

It is important to measure the amount of paraprotein present in your blood and/or urine as this reflects the extent of myeloma at the time of diagnosis. This information provides a baseline which can be compared with later results to see how you are progressing.

BONE MARROW BIOSPY

A bone marrow biopsy involves taking a sample of bone marrow, usually from the back of the iliac crest (hip bone) to count the number of plasma cells present and to see how well the bone marrow is functioning. Under normal conditions plasma cells make up less than 5% of all the cells within the bone marrow. In myeloma the number is frequently over 30% or more.

The bone marrow biopsy may be done in the haematologist’s rooms or clinic under local anaesthesia or, in selected cases, under a short general anaesthetic in a day procedure unit. A mild sedative and a pain-killer is given beforehand and the skin is numbed using a local anaesthetic. This is given as an injection under the skin. The injection takes a minute or two, and you should feel only a mild stinging sensation.

After allowing time for the local anaesthetic to work, a long thin needle is inserted through the skin and outer layer of bone into the bone marrow cavity. A syringe is attached to the end of the needle and a small sample of bone marrow fluid is drawn out - this is called a ‘bone marrow aspirate’. Then a slightly larger needle is used to obtain a small core of bone marrow which will provide more detailed information about the structure of the bone marrow and bone - this is known as a ‘bone marrow trephine’.

A small dressing or plaster over the biopsy site can be removed the next day. There may be some mild bruising or discomfort, which usually is managed effectively by paracetamol.