False-positive results for ATTR-CA may occur in: AL-amyloidosis, hydroxycloquine-induced restrictive cardiomyopathy, rare variants of CA associated with chronic kidney disease (AapoAI, AApoAII, ApoAIV or Aβ2M amyloidosis) or in radiotracer persistence in the blood pool. This evidence concerns the gene APOA4 and restrictive cardiomyopathy.