Acute intermittent porphyria
Diagnosis and Testing
How accurate is the genetic testing for acute intermittent porphyria?
Accuracy of the genetic testing may change based on which laboratory is performing the test. However, the testing generally find 98% of genetic mutations. This means that about 2% of people with changes in the HMBS gene will have a negative genetic test.
Acute Intermittent Porphyria. Gene Reviews. (http://www.ncbi.nlm.nih.gov/books/NBK1193/)