Keeping Blood Products Cold During Dispensing

Tests show that gel blankets significantly help maintain temps below 6oC

Test Blood Bag Warming using reusable ice packsOn a recent visit to a blood bank customer who uses Safe-T-Vue 6, we learned something that we felt was worth sharing. During the approximate 10 minutes that it often took to do paperwork and cross-matching, they sometimes experienced the Safe-T-Vue 6 (STV-6) “tripping.” This caused concern that the blood product may have been compromised by room temperature exposure, even for a seemingly short time period.

To address this problem, they began using refrigerated gel blankets (reusable ice pack sheets) to keep the blood product cool. Taking this simple step of placing the blanket around the blood bag(s) during preparation and before transport to the ER/OR has given them confidence that the blood product has been kept cool, and the STV-6 provides visual indication and reassurance that 6°C has not been exceeded.

Wanting to learn just how much the gel blanket helped, we turned to Marielle Smith, Technical Service Scientist in our Temptime Lab, to do some testing. You may be surprised by what we learned.

Read this VUEPOINT to see the test procedure and learn from the detailed data we gathered. It may inspire you to try gel blankets in your blood bank!

Tests to compare blood bag warming with and without refrigerated gel blankets

When blood banks are preparing refrigerated blood bags for transport to the OR/ER, there is limited time for blood bank personnel to record the necessary patient information (cross-check, paperwork, etc.) before the blood approaches critical temperatures. Many blood banks use Safe-T-Vue 6 for exactly this reason.

Previous studies have shown that bags warm quickly to temperatures (6.0°C in less than 10 minutes) rendering the blood unsuitable for use. Results from this new study, however, demonstrate that using a refrigerated gel blanket (such as the Thermafreeze Reusable Ice Pack Sheet) makes a significant difference in slowing the warming rate when the blood product is removed from refrigeration to typical room temperature conditions.

Test procedure setup

A test was performed to assess whether using a refrigerated gel blanket can add to the longevity of the blood bags upon removal from refrigerated storage (1°C – 4°C).

The test was setup to collect temperature data as follows:

1. Control, single bag with no gel blanket
2. Single bag with small gel blanket, cutout window (to view Safe-T-Vue 6)
3. Three bags with larger gel blanket

Six (6) bags of 350 mL simulated red blood cells volume were used for scenarios 1 and 2, and 18 bags were used for scenario 3.

Reusable Ice Pack Sheets (e.g., gel blanket) were obtained and cut into different dimensions to allow for testing either a single bag (with a window cut-out to view the Safe-T-Vue 6 indicator) or 3 bags side-by-side.

Small gel blanket with viewing window for 1 bag

Large gel blanket for 3 bags

Temperature measurement

Calibrated temperature probes were inserted into each of the simulated blood bags. Calibrated electronic thermometers (accuracy of at least ±0.1°C) were used to record the temperature of the fluid inside the filled blood bags.

After pre-conditioning in the refrigerator (maintained between 1°C to 4°C) for at least 24 hours, the bags and the gel blankets were removed and placed lying flat on a counter-top at room temperature conditions (19°C ± 1°C with 50% R.H). A timer was set to count-up mode and temperature readings were recorded at one minute intervals until the temperature inside the bag reached 6°C.

Test results

The data points on the graph below show the gradual warming of the bags as the refrigerated blood bags warm to 6.0°C in room temperature conditions when the blood bag is either wrapped in a refrigerated gel blanket, or left as is upon removal from refrigerated storage (control).


  • Without using a gel blanket, blood bags warmed from 3.2°C to 6.0°C in approximately 9 minutes
  • Using a small gel blanket (with a window cut out to allow for visual interpretation of the Safe-T-Vue 6 indicator), blood bags warmed to 6.0°C in approximately 25 minutes
  • Using a large gel blanket for testing up to 3 bags side-by-side, blood bags warmed to 6.0°C in approximately 32 minutes

Conclusions and recommendations

The results presented in this report support that a pre-conditioned refrigerated gel blanket can be wrapped around blood products to keep the blood below 6°C for an extended period of time – while blood bank personnel are preparing the blood for transport to the ER/OR.

When a simulated blood bag was wrapped in a refrigerated gel blanket upon removal from refrigerated storage (1°C to 4°C), the bag warmed to 6.0°C within about 25 to 32 minutes on a counter at room temperature conditions. As an added precaution, a Safe-T-Vue 6 indicator can be used to provide irreversible visual indication of temperature excursions beyond 6.0°C.

Order free samples of Safe-T-Vue 6

Reduce RBC and FFP Waste, Improve ROI

Learn more from this Blood Transport and Storage Initiative that resulted in significant ROI

by Jeff Gutkind, Business Development Manager

I recently read an article in the journal Transfusion1 in reference to reducing red blood cell (RBC) and plasma (FFP) waste.  The study showed significant reduction in RBC and FFP waste by using a new blood transport and storage system, and a significant return on their investment in the new system (estimated savings of $9000/month for their institution).

While the article doesn’t speak to temperature indicators, it does seem to validate that there is a trend toward cooler storage in the OR being considered “intraoperative storage,” which is significant.

For those of us sensitive to blood waste (and associated costs) due to time-temperature issues, this study has a wealth of valuable information and powerful messages:The article cites a national waste rate for hospital-issued blood products ranging from 0% to 6%, and a common reason for blood waste being inadequate intraoperative storage.2

  • The article describes how most of their blood waste was from either temperature or time (away from the blood bank) excursions, and that 70% of those losses came from blood product issued to the OR in coolers.
  • In the second paragraph they state that “AABB standards require red blood cell and plasma units to be maintained at a temperature of 1-10°C during transport and 1-6°C during intraoperative storage.
  • They go on to state (under Materials and Methods) that “holding product in the OR represents a storage condition“….. and “the storage (1-6°C), not the more lenient transport (1-10°C) temperature range needed to be maintained.”

Their previous procedure was to issue blood products to the OR in off-the-shelf commercial coolers that were validated to hold product at 1-10°C for 8 hours. They changed to a new, more expensive cooler that incorporated specialty phase change material that is validated to hold 1-6°C for 18 hours. As a result of the new system and strategy, they have improved their “storage” compliance to 1-6°C and reduced waste from 1.20% to 0.06%, which they calculate to save the $9,000 per MONTH.

The result of this study suggests that incorporating a new, longer duration blood shipping and storage container has allowed the OR to store blood for up to 18 hours at 1-6°C while meeting AABB’s more strict guidelines and has produced significant cost savings and notable return on investment 

It would be interesting to see the savings if they incorporated a Safe-T-Vue 6 indicator in this study.


1. Brown MJ, Button LM, Badjie KS, Guyer JM, Dhanaroker SR, Brach EJ, Johnson PM, Stubbs JR. Implementation of an intraoperative blood transport and storage initiative and its effect on reducing red blood cell and plasma waste, Transfusion 2014;54: 710-07.

2. Heltimiller ES, Hill RB, Marshall CE, Parsons FJ, Berkow LC, Barrasso CA, Zink EK, Ness PM. Blood wastage reduction using Lean Sigma methodology. Transufions 2010;50: 1887-96.