Does anyone know about porphyria?

I am hoping that someone knows about porphyria testing and diagnosis.  I have read different things on the internet as to the accuracy of testing and wondered if any testing can 100% diagnose the disease.  I have had more than one attack with symptoms of porphyria but no one tested for it.  I have heard that the testing in between attacks may not show anything but maybe other tests for porphyrins in the blood or other can show up something when there aren't symptoms.  I really want to know what mystery illness I had.