Temperature-Sensitive Labels for Containers of RBCs

Abstract

Temperature-sensitive labels are adhesive tags that display color changes at preset temperatures. There have been no studies of the suitability of this technology for measuring the temperature of blood components during transportation and storage. We used a digital thermometer to measure temperature in different locations inside containers of RBC as they were allowed to warm to ambient temperatures following removal from refrigeration. We compared these temperature readings with those of 3 temperature-sensitive labels. These labels are marketed to alert transfusion services if the temperature of blood bags exceeds 10 degrees C, which is the maximum permissible by Food and Drug Administration and American Association of Blood Banks requirements for transporting RBCs. The contents of refrigerated RBC units changed from one homogeneous temperature to a range of temperatures when containers were allowed to warm (undisturbed) to ambient temperatures. Color changes of all 3 temperature-sensitive labels correlated more with core compared with surface temperatures of RBCs units. These devices add an additional dimension of safety to the conventional 30-minute rule, which limits storage of blood components at ambient temperature to 30 minutes.

Thermometry of Red Blood Cell Concentrate: Magnetic Resonance Decoding Warm Up Process

“…4) the term surface temperature for maximal temperature is justified. Temperatures at RBC pouch’s surface were, however, inhomogeneously distributed as previously demonstrated by Johnson et al [10]. Surface temperature therefore represents the upper temperature bound reached at thinner layers of the pouch.…”

“…Both methods however give only rather crude estimates of RBC temperature: According to the well-established “30 minutes rule in transfusion medicine” RBCs may be returned to 1 to 6°C storage within 30 min as general upper time limit, whereas neither RBC storage and ambient temperature nor sample volume is taken into account [7], [8], [9]. Controlling temperature by temperature indicators or time–temperature integrator units attached to the surface of the RBC pouch implies that surface temperature well represents sample’s core temperature, which can but doesn’t have to be true [10], [11], [12], [13], [14], [15]. Facing worldwide decreased availability of lifesaving RBC challenges a more precise evaluation of correlations between maximum (surface), mean and minimum (core) temperature in RBC units removed from stock to prevent unnecessary wastage of blood components and, if transfused, ensure minimal risk to patients [1], [2], [3], [16], [17].…”

Temperature-Sensitive Indicators for Monitoring RBC Concentrates Out of Controlled Temperature Storage

“…TIs vary in their accuracy of reflecting core temperatures. 10 For Check-Spot, which is calibrated to a temperature limit of 10°C, the final color change occurs between 10°C and 11.9°C RBC concentrate core temperature. 10 However, Thermoindikator V4 has "only" been validated to reflect RBC concentrate temperature after storage at 22°C for 30 minutes (and not to reflect RBC concentrate core temperature at 10°C).…”

“…Verification studies, including lot-to-lot analysis, have been published previously. 10 Thermoindikator V4 is a prototype of a self-adhesive label that contains photochromic pigments that fade depending on both time and temperature. The labels' pigments are activated by a small UV charging device.…”

Strategies to reduce wastage of red blood cell units

“…To monitor the core temperature of blood products returning to the transfusion laboratory, we used temperature‐sensitive labels (Fig. a,b) and determined the extent of colouring correlating with a core temperature of 10°C. The median time before refrigerated RBCs reached a core temperature of 10°C after being placed at room temperature was 25 min (Fig.…”