FAQs: Safe-T-Vue

Q: At what temperature should blood (or the temperature-sensitive product being monitored) be prior to attaching Safe-T-Vue?

Blood temperature should be as cold as possible (between 2°C and 4.5°C is recommended). A low start temperature is critical to delivery of blood/components/products within compliance temperature.

Q: How long can the blood bag, or temperature-sensitive product being monitored, be out of the refrigerator (to avoid unnecessary warming during handling, labeling, and packing)?

It depends on the temperature being monitored. For 6°C monitoring temperature, the blood product should always be accompanied with a cold pack that has been stored in the same refrigerator to maintain temperature of the blood.

For a 10°C monitoring temperature, RBCs and most temperature-sensitive products may be out of refrigeration no more than 10 minutes before issuing. Use of a cold pack from the same refrigerator accompanying the product is always recommended.  If RBCs and temperature-sensitive products are out of refrigeration for more than 10 minutes without an accompanying cold pack, it should be re-refrigerated for a minimum of 90 minutes before issuing.

Use of a cold pack in direct contact with the bag will help maintain temperature of blood during the dispensing process. Keep multiple cold packs in blood refrigerator to assure cold pack temperature to be same as blood bag.

Q: Does the temperature of the room have any effect on Safe-T-Vue?

Room temperature will affect heat transfer of anything in it. Therefore, a cooler room temperature may slow down the warming rate of blood bags or temperature-sensitive products once they are removed from the refrigerator. The Safe-T-Vue will only monitor the temperature of the blood bag on to which it has been adhered.

Q: Cold bags often condense moisture on them after removal from the blood refrigerator. Do I need to remove it before applying a Safe-T-Vue to the bag?

Just before applying Safe-T-Vue, remove excess moisture by using a dry lab wipe or paper towel on the surface where the Safe-T-Vue is to be applied.

Q: Do busy blood refrigerators affect blood temperature?

Refrigerators with high door counts should be high recovery units to assure maintenance of blood at required safe temperature. An increase of 3 to 4°C can take place in air temperature of a blood refrigerator held open for 30 seconds.

Q: Do you have any protocols for packing blood products being sent to the OR or transport to another location?

When packing with wet ice or reusable cold packs, follow the packing instructions provided with your validated shipping container. The top-most layer should always be wet ice or cold packs to keep warm air from the blood bags and/or temperature-sensitive products being monitored. Cooler contents warm from the top down. Avoid direct contact between wet ice packing and blood or temperature-sensitive products being monitored unless specified by your packing protocol. Use an adsorbent pad to act as an insulator between the blood bags or temperature-sensitive products and the wet ice or cold pack. Reference: ARC JOB AID, BSD73.200M/JA02 (8/04).

Q:What type of thermometer should should be used during validation of Safe-T-Vue products?

For validation of Safe-T-Vue 6, Safe-T-Vue 8, and Safe-T-Vue 10, we suggest using an electronic thermometer and thermister probes inside simulated blood bags (±0.1°C stated accuracy). Avoid surface measurement such as infrared thermometers (±1.5°C typical stated accuracy) or a glass thermometer in contact with only the surface of the bag.

For a detailed validation protocol, visit our web site at www.williamlabs.com, go to “References and Documents”, then download QAP 0300 incoming inspection protocol for the Safe-T-Vue product you are using (Call Customer Service at 800/767-7643).

Simulated blood bags may be prepared using the appropriate volume of water and glycerol or Copper Sulfate-similar solution. Reference: Technical Manual, American Association of Blood Banks.

Q: How long can the indicators remain on stored units once applied?

Safe-T-Vue indicators may remain on units as long as the red color has not been observed.

Q: How can I be certain our blood bags are uniformly the same temperature in our refrigerator?

Uniform temperature of all blood bags in any given refrigerator depends on the recovery rate of the refrig­erator after its door has been opened and air circulation around bags. One way to assist a refrigerator with cooling of blood bags is to be certain the bags are stored in a vertical position with air space around them. Bags lying on top of each other require longer times to reach refrigerator temperature.

Q. How do I interpret the color change of the temperature indicator?

Safe-T-Vue 6

Safe-T-Vue 10





A. When using Safe-T-Vue 6, Safe-T-Vue 8, and Safe-T-Vue 10, it is important to properly interpret Safe-T-Vue’s color change as follows:

1. The color change may take place over about 1°C ending at Safe-T-Vue indicating temperature. (Refer to the lot specific Quality Assurance document included with each shipment and posted in the Support section of this website.)

2. Temperature has been reached ONLY when the entire white area is colored from a mottled rose to solid red. Sometimes a pinkish hue or cast may be observed in the white disk at the start. THIS IS NOT A TEMPERATURE CHANGE. Depending upon the light source, it is a muted refraction of the bottom red disc. It is clearly distinguishable from the color change of rose to red. Use of a positive control is recommended to assure correct interpretation.

3. The start of the color change is typically in spots of light rose to red anywhere in the white area, but is not completed until the white area has turned completely to solid red.

4. When you observe a red color indication but are certain the blood or temperature-sensitive product being monitored is below the color-indicating temperature of the Safe-T-Vue product you are using, please review the following list of actions and/or environmental factors to determine what may be causing the red indication:

a. Handling of Safe-T-Vue at the Wrong End. Indicator should be handled ONLY by the round, color-coded label end. Safe-T-Vue is extremely sensitive to its environment and touching or grasping the red end of the indicator will usually result in activation.

b. Improper Activation. When activating, be sure to press ONLY the white, color-coded round label end into the red end by pressing only on the color-coded round label.

c. Premature Removal of Paper/Foil Lid. Peel the paper/foil lid ONLY after attaching the Safe-T-Vue Temperature Indicator to the blood bag or temperature-sensitive product being monitored. Peeling before attachment may cause activation.

d. Excessive Time Taken to Activate. For Safe-T-Vue 8 and Safe-T-Vue 10, activation should occur within 15 seconds from the time Safe-T-Vue is removed from the refrigerator. Refer to separate instructions for activating Safe-T-Vue 6. Use of a cold pack will help maintain temperature of blood during dispensing process by placing cold pack under bag. Keep multiple cold packs in blood refrigerator to assure cold pack temperature to be same as blood bag.

e. Busy Refrigerator. Check door counts since an increase of 3 to 4°C can take place in the air temperature of a blood refrigerator held open for 30 seconds.

f. Location in Refrigerator. A high door count  may warm Safe-T-Vue if it is located in an area of the refrigerator where it is swept by warm room air. Usually the best place to keep Safe-T-Vue is towards the back of a lower shelf.

g. Blood Not Cold Enough. Blood received from a supplier may be close to 10°C on arrival. Be certain blood is cooled in the refrigerator a minimum of 90 minutes before release from the blood bank.

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