Diagnosis of Raynaud's phenomenon by thermography

Background/aims: The aim was to clarify whether cold fingers before a moderate cold stress test can predict a prolonged delay (more than 20 min) in rewarming, as diagnostic for Raynaud's phenomenon. Methods: A retrospective study was conducted on 71 patients suspected of suffering from Raynaud's phenomenon. The thermal gradient from the metacarpophalangeal joints to the finger tips was calculated for each finger and cold fingers were defined by a temperature difference of more than −0.5°2C. Results: Combining the frequencies of cold fingers with a diagnosis Raynaud's phenomenon resulted in a sensitivity of 78.4%, a specificity of 72.4% and diagnostic accuracy of 74.0%. Conclusion: Based on a positive predictive value of 58.5%, it was concluded, that a prolonged delay of rewarming after a cold stress test cannot be predicted sufficiently by the presence of cold fingers alone, and that a cold stress test is necessary to confirm the diagnosis objectively.