The analysis of sensitivity, specificity, positive predictive value and negative predictive value of cold provocation thermography in the objective diagnosis of the hand-arm vibration syndrome

The diagnosis of digital artery vasospasm in the hand-arm vibration syndrom e (HAVS) is clinically based, and the need for an accurate objective test t o support the diagnosis has been highlighted. This study aims to analyse th e potential of cold provocation thermography (CPT) to fulfil this role. CPT was performed on two groups of subjects: 10 controls and 21 patients with Raynaud's phenomenon (RP) secondary to HAVS. After taking a pre-cooling ima ge, patients donned latex gloves and immersed their hands in water at a tem perature of 5 degreesC for 1 min. The patients removed their hands from the water and discarded the gloves, and further images were taken every 30 s f or 10 min. On each image, the temperatures of the tip and base were analyse d for each digit. The sensitivity, specificity, positive and negative predi ctive values for fingertip temperatures only, fingertip and fingerbase temp eratures combined, and fingertip temperature, fingerbase temperature and te mperature gradient combined were determined. Patients with RP secondary to HAVS demonstrated significantly lower finger tip and base temperatures and lower digital temperature gradients at all time intervals when compared wit h controls (P< 0.01, Student's t-test), CPT has good sensitivity, specifici ty, positive predictive value and negative predictive value; it strongly su pports the clinical diagnosis of digital vasospasm.