Design and evaluation of cryodevice, an easy to use apparatus for maintenance of optimum temperature during cryoglobulin assay

Introduction: Maintenance of temperature during collection and transport of blood is an important pre-requisite for cryoglobulin assays. In this manuscript, we describe ‘cryodevice’, a low-cost device for transportation and/or incubation of vials of whole blood at 37°C. Such a device would reduce false negatives in cryoglobulin assays. Method: The ‘cryodevice’ takes the embodiment of a portable, light, insulated water bath, which can be used as an incubator in a plugged-in state, or as a transport container after it is set up and disconnected from the power supply. The design of the cryodevice is described here, with focus on its construction and electronic control circuit. Computer simulations and in vitro trials were performed to study the temperature drop in the blood samples placed in the device. Subsequently, the cryodevice was also used with actual patient blood samples. Results: Thermal simulations and in vitro testing of the cryodevice predicted that the design would meet the temperature maintenance goals. When the cryodevice was put in to use for screening 45 patient blood samples, it helped identify positive cryoglobulinemia in three of the samples. Conclusion: The description of the cryodevice envisions enabling the construction of a low-cost device in resource-limited healthcare settings in India created with locally available resources. On testing, the device was found to be satisfactory in performance and is expected to bring down incidences of false negatives in cryoglobulin tests.