Hi Lucinda,

The diagnostic test currently done involves testing for the presence
of the dysferlin protein, using an antibody which recognizes
dysferlin. Currently this is done using a muscle biopsy, although a
test is currently being developed do detect dysferlin in a certain
type of white blood cells, which would be convenient for a lot of
people because it wouldn't necessitate the trouble of a muscle
biopsy...
As I understand it, performing the test is not all that
technically difficult; the antibodies which have been developed for
dysferlin detection are quite sensitive and are commercially
available. There is a difficulty in that patients who have a
mutation in one gene sometimes show abnormalities in other muscle
proteins as a secondary effect. For dysferlin, patients who have
genetically confirmed muscular dystrophy of other types have been
shown to sometimes exhibit abnormal expression or localization (not
in the proper place within the cell) of dysferlin. So the protein
test is very useful, but probably shouldn't be the sole criterion
for a diagnosis--a patient's age, history, symptoms, and other tests
such as CK, EMG, etc. should be taken into account.
I don't know specifically of laboratories in New Zealand who
perform the test (perhaps the MDA of NZ would be able to provide
this information?) I do know that the Children's Hospital in
Westmead, Sydney does this sort of testing and is currently
conducting research on dysferlin deficiency.

Hope this helps..best of luck to you!
Brad