[tm648]

M-Protein vs. Igg

by tm648 on Mon Apr 01, 2013 2:41 pm

I recently had an evaluation by an oncologist for possible multiple myeloma. The oncologist did a number of tests, including an Igg test, but not an SPEP test for M-protein. When I asked him about that, the oncologist said that he didn’t need to order an SPEP, because the total Igg test that he did was “more sophisticated.” (By the way, my Igg was 2800 and the tests for all the CRAB symptoms were negative). So my question is: What’s the difference between Igg and M-protein, and should I press my oncologist to assess my M-protein? Thanks in advance.

[Multibilly]

Re: M-Protein vs. Igg

by Multibilly on Mon Apr 01, 2013 6:02 pm

Those statements are bit peculiar based on my own experience.

IgG is one of several immunoglobulins (proteins) that one has in their blood. Usually, if one immunoglobulin like the IgG shows a higher-than-normal concentration and is accompanied by lower-than-normal concentrations of the other immunoglobulins (IgA, IgM, etc), this often suggests that there are also monoclonal concentrations of that immunoglobulin that are present in your blood (meaning you could be at some stage of multiple myeloma). Your IgG is high according to the standards used in my tests (normal range is 700-1600 mg/dl), but different labs have different ranges.

The SPEP measures the M-Spike (aka paraprotein) level in your blood that represents the amount of abnormal single clone (aka monoclonal) immunoglobulins. The "M" in M-Spike" stands for "Monoclonal".

If your IgG is high, you want to still get an SPEP, as well as having your Free Light Chains measured and the other tests I mention further below.

You say you have no CRAB symptoms. Does this mean that you already had a full skeletal XRAY survey of your entire body and a metabolic panel? No CRAB is a great thing.

If my IgG were high, I would also be asking about getting a bone marrow biopsy to check for the amount of any abnormal plasma cells in your bone marrow. This is usually accompanied by testing the chromosomes of the abnormal plasma cells for any prognostic indicators associated with multiple myeloma and includes a test called "FISH". A bone marrow biopsy is the golden test for determining if you have multiple myeloma or not.

My family doc first found that I had a high IgG and I then had all of the above tests done to later confirm a diagnosis. And I'm about to get most of these done again next week as part of routine, ongoing checkups.

Is your oncologist a Multiple Myeloma specialist that sees many multiple myeloma patients every year? If not, I suggest you seek one that lives and breathes this disease on a daily basis.

Good luck!

[Dr. Adam Cohen]

Re: M-Protein vs. Igg

by Dr. Adam Cohen on Thu Apr 04, 2013 9:37 pm

Hi tm648,
I agree with Multibilly. A high IgG level is non-specific. It can be a sign that there is a monoclonal protein present, which can be seen in myeloma, MGUS, and related diseases, but it can also be a reaction to some other process going on in the body. This is called a polyclonal gammopathy, and can be caused by chronic infections, autoimmune diseases, liver problems, among other things. I would recommend getting an SPEP, serum immunofixation, and serum free light chains with ratio for starters. This should be able to distinguish between a monoclonal and polyclonal gammopathy, and further appropriate work-up can be determined from there.