Table 1: Comparison of noninvasive techniques for assessing endothelial function.

TechniqueEquipmentCostSkill levelTest timeValidityReliabilityRef

PWAApplanation tonometryMedium
US$15,000
Low35 minsMedium*Medium-high*
d = 0.9–2.3%
[69]
FMD(i) Ultrasound
(ii) Tourniquet
High
>US$50,000
High20 minsHighMedium
CV: 14–50%
[1016]
PlethysmographyStrain-gaugeLow
US$10,000
Med.30 minsMediumMedium
CV: 8–27%
[1720]

FMD: flow-mediated dilation; CV: coefficient of variation; d: sample bias (mean difference); PWA: pulse wave analysis. *Further study is needed to corroborate these findings.