Diagnostic Tests

First a few randoms:

best screening test for hereditary angioedema = C4 always low in HAE; if not low then NOT HAE     addendum to answer C1INH will be low in type I (but normal in type II with dysfunctional enzyme)

best screening test for porphyria (in general) = plasma porphyrins

best imaging study for spinal dysraphism = ultrasound is efficient screening in newborns up to 6 months old (but is inadequate for older infants and children, who need MRI)