Device for Carrying Blood Samples at 37°C for Cryoglobulin Test

To reliably transport blood samples for cryoglobulin analysis, we have created a sample transport device containing a mixture of two waxes that solidifies at 38°C andmaintains sample temperature at 38°C. Samples arriving at the laboratory at 37 to 38°C in-creased to 95 % from 34%with the use of the device. Cryoglobulin is a common and simple clinical immunologylaboratory test that requires the blood samples to be trans-ported to the laboratory, without cooling, at 37°C (1, 5, 6). To achieve this, samples were generally delivered by hand to the lab-oratory in an insulated container containing warm water. How-ever, the samples often arrive at the laboratory at a temperature of 36°C or below. Also, it was difficult to regulate the exact temper-ature of the “warm water, ” resulting in occasional use of water at a temperature that was too low or even too high (4). These difficul-ties have prevented standardization of the cryoglobulin assay and limited use of the assay (5, 6). To transport blood samples at 37°C easily and reliably, we designed a carrier containing a material that solidifies at 37°C or 38°C. We created such a material with n-docosane and n-eicosane (from Sigma-Aldrich, St. Louis, MO), which are long-chain alkanes (paraffin waxes) with no specific toxic properties and which have high heat of fusion and melting at 43.5°C and 36°