UPDATE:
In order to ensure consistent product performance Medical Electronic Systems is now recommending that opened QwikCheck Bead QC Kits be stored @ 2-8°C (36-46°F). The expiration date assumes that QwikCheck beads are stored in their original containers and tightly capped to prevent evaporation. QwikCheck beads are stable and show no loss of expected performance characteristics after transport/storage over a period of 72 hours at the temperature range of -20°C to +37°C (-4°F to +99°F).