WHILE AMYLOID PET IMAGING IS AN ESTABLISHED METHOD FOR AIDING DIAGNOSIS OF AD , IT IS SIGNIFICANTLY MORE EXPENSIVE , INVASIVE AND SPECIALIST- DEPENDENT THAN BLOOD TESTS .
F E A T U R E
WHILE AMYLOID PET IMAGING IS AN ESTABLISHED METHOD FOR AIDING DIAGNOSIS OF AD , IT IS SIGNIFICANTLY MORE EXPENSIVE , INVASIVE AND SPECIALIST- DEPENDENT THAN BLOOD TESTS .
from participants with amyloid PET imaging and demographic data from the 1Florida Alzheimer ’ s Disease Research Center . Quest introduced the AD-Detect test to physicians in early 2022 .
The investigators also evaluated the performance of the blood test by different interpretative ranges based on different cutoffs , or amyloid levels in the blood . Proposed guidelines from the National Institutes of Aging recommend blood biomarker testing account for different ranges by cutoff levels , including an intermediate range , to support clinical decision making .
Key findings :
High NPV across populations : The test ’ s negative predictive value ( NPV ) was 99 % ( at the highest cutoff of 0.170 ) in a population with moderate prevalence of AD ( 40 %) as determined by PET-positivity . NPV represents the likelihood a disease is not present in a given population . The investigators then applied the NPV of 99 % to the population of 6,192 deidentified specimens tested by Quest for Aẞ42 / 40 . They determined that 40 % of that population could reliably forgo additional evaluation by PET , which costs about US $ 5,000 per scan .
High sensitivity for AD PET-positivity at lower cut off : The test was 91 % sensitive for detecting AD , as determined by PET scan at a cutoff of 0.160 in a population with moderate prevalence of PET-positivity of 40 %.
In the same population and cutoff , the specificity was 76 %. The same investigative
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