At 2000-04-11 22:27 +0100, Graham Bishell wrote:
>Methods for the detection of cryoglobulin are not particularly advanced.
>We have been looking at trying to make the method less subjective by
>measuring absorbance change upon warming up serum/plasma, with some
>success. Has anyone used a similar or other approach to reducing the
>subjectivity of cryoglobulin detection.
Plasma (EDTA) viscosimetry is possible to use. Probably there is no
quantitative method of cryoglobulins, but a qualitative measurement may be
sufficient in this case. Together with clinical symtoms (bad circulation in
hands etc in cold environment) the diagnosis should be sufficiently certain.
After storage at 4 C and gentle mixing of a plasma sample, the viscosity as
measured at 37 C in a Brookfield micro viscosimeter stabilizes within 3-4
minutes if cryoglobulin is not present. However, if cryoglobulins are
present the viscosity continues to decrease for 10-40 minutes.
Because of aggregation also small amounts of cryoglobulin will
significantly affect the plasma viscosity. This is in fact the cause of the
clinical symtoms. Upon heating to 37 C the cryoglobulins will slowly
de-aggregate and this can be seen as a continuosly decreasing viscosity.
Few laboratories are doing plasma viscosity, but it is a reliable method
and samples should be sent for viscosimetry if cryoglobulinemia is suspected.
Mr Sten Öhman, PhD
Sten Öhman, PhD
Elfin Lab & Milieuconsult
P O Box 133
S-590 70 Ljungsbro
Sweden
Tel Nat: 013-368940 Int: +46 13 368940
Fax Nat: 013-368941 Int: +46 13 368941
[log in to unmask]
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|