[dolphinnose]

M-spike - does absolute or percentage level matter?

by dolphinnose on Tue Apr 28, 2015 9:03 am

Serum protein electrophoresis (SPEP) reports the M protein as percentage and absolute value.

My last SPEP M protein was 1.3 g/dl, but a 16.5 percentage of total protein of 7.9. The latest test has 1.28 g/dl, but a 17.7 percent of total protein of 7.2.

Should I infer the M protein increased or decreased from the above?

Thank you

[Cheryl G]

Re: M-spike - does absolute or percentage level matter?

by Cheryl G on Tue Apr 28, 2015 3:05 pm

Hello dolphinnose,

It's the absolute level of your M-protein / M-spike that matters.

That said, a change from 1.3 to 1.28 g/dL is really no change at all. There are inaccuracies in the way M-spikes are measured that mean that "changes" of a couple of tenths of a g/dL really shouldn't be too much concern. They can just be measurement error. This is particularly true for people who have IgA myeloma, where the M-spike is more difficult to measure than it is, for example, in IgG myeloma.

(I realize from your previous postings that it is your IgG that is elevated. I just mention the issue of M-spikes with IgA myeloma for anyone else who may be reading this and might have IgA myeloma or MGUS.)

[dolphinnose]

Re: M-spike - does absolute or percentage level matter?

by dolphinnose on Wed Apr 29, 2015 3:53 am

Thank you, Cheryl, for taking time to explain.