Objectives: Thermograms have shown that deep vein thrombosis (DVT) causes an increase in temperature in the leg. We have studied for the first time, the viability of measuring spot skin temperatures using a hand-held instrument called a thermo-comparator as an inexpensive, simple and reliable method of excluding the diagnosis of DVT.
Methods: A total of 33 patients with suspected DVT had spot skin temperatures taken on specified areas of each leg using the instrument. The results were compared with duplex scans of the patient and with venography in some patients.
Results: There was a mean temperature gradient of 3.38°C down each normal leg. All 10 patients with DVT confirmed by duplex scan or venogram also had raised temperatures compared with surrounding areas, without the normal temperature gradient down the leg (true positive, 100%). This instrument did not have any false negatives and achieved 100% sensitivity and 100% negative predictive value.
Conclusions: The thermo-comparator excluded a diagnosis of DVT in 39% of patients and has the potential for use in primary care as a screening tool to reduce the number of patients sent to hospital unnecessarily.
