Temperature Monitoring in the Medical Laboratory

November-December 2013 - Vol.2 No. 6 - Page #16
Category: Temperature Monitoring

The monitoring of temperature sensitive areas to maintain a constant, regulated state of control for products affected by temperature changes is critical for proper medical laboratory operation from a quality perspective. Even though all labs strive to employ the best staff and use the best analyzers and equipment, the ultimate quality of laboratory services is equally dependent upon the integrity of the reagents and media used throughout the lab. All of the consumable reagents and control material used in the pre-analytic and analytic phases are sensitive to temperature extremes and fluctuations. Therefore, the manufacturers of these reagents specify tolerance ranges for their products, within which they warrant the efficacy and accuracy of those products. Failure to store these items within the designated temperature range, or using them to test specimens outside of the designated range significantly increases the risk of obtaining erroneous results. 

Similarly, there are several pieces of equipment that must be run within specified temperature ranges in order to operate according to specifications. If there are fluctuations in the environmental temperature, equipment calibrations can become invalid and will need to be re-run. Due to the critical necessity of maintaining specific temperatures during both active testing operations and static storage or transport, the methods by which that maintenance takes place must be targeted, effective, and perpetual.

Evolution of Temperature Monitoring
The pathology department at Irwin Army Community Hospital (IACH) located in Fort Riley, Kansas, operates a full service anatomic and clinical pathology laboratory with services that include chemistry, hematology/coagulation, histology, microbiology, transfusion services, and urinalysis. We also utilize several military and commercial reference laboratories (under contract to the Army) to enhance our testing menu and to better support our patients. We currently have 50 anatomic/clinical FTE’s plus two administrative FTE’s within our organization and we also have two ancillary clinic laboratories, both located on Fort Riley, which support the patient centered medical homes based at the clinics. Our daily test volume is approximately 4,500 tests per day.

The process of temperature monitoring has undergone tremendous technological advances in the last two decades. Older systems employed liquid thermometers (either mercury or spirit fluid) immersed in a liquid and staff took recorded temperatures manually on a paper log sheet at designated times during the day. These intermittent samples of temperature stability did not provide a comprehensive view of storage conditions during off-shifts and the process did little to prevent system failures or alert staff of such events. In addition, the logging process was subject to both measuring and transcription errors. 

Given the sensitive nature of the specimens, reagents, and other products used daily in the lab, we are fortunate to have progressed to automated systems that are perpetual and layered to provide redundancy and increased confidence in the fidelity of the measured temperatures. Almost every refrigerator and freezer used in the laboratory has an integrated, calibrated thermometer, which digitally displays the current temperature and records historical data. Most of these integrated systems have both a visual and audible alarm to notify specific staff if temperatures stray from the designated normal operating ranges. Now that today’s systems offer back up power sources, remote viewing, and other preventive measures, the integrity of laboratory storage and delivery devices is quite sound.

Specific Temperature Challenges
As all of our laboratory sections depend on proper temperature management, we rely heavily on our monitoring systems to insure the quality of our reagents and the testing operations themselves. We store reagents, blood and blood products, tissue, calibrators and controls, as well as patient samples in our refrigerators and freezers, and each of these has various, but specific, manufacturer-determined temperature ranges that must be maintained. While many reagents have wider temperature tolerances, blood and blood products, stored tissues, and calibrators have tighter ranges and are extremely sensitive to variations. In addition, several tests, such as those related to blood gas determinations, alkaline phosphatase, and serology, are particularly sensitive to temperature variations. Likewise, since calibrators are used to evaluate and adjust the precision and accuracy of instruments, and to eliminate or reduce bias in the result values over that instrument’s analytic range, any environmental factor that can affect the calibration curve (such as a temperature change) can have a profound effect on the calibration and therefore lead to inaccurate measurement of clinical values.

The management of temperature sensitive specimens, reagents, and other testing materials faces several challenges to ongoing performance and maintenance. Among the more obvious is the requirement of providing an uninterrupted and stable source of power to all refrigerators and freezers. We mitigate the risk of a power failure by strategically placing and plugging our refrigerators and freezers that hold reagents and specimens into emergency power outlets. If commercial power is interrupted, our hospital generators will maintain power to these special outlets (and other emergency equipment) until the master is repaired. 

When it comes to any process that must be maintained in the lab, the risk of human error cannot be underestimated. Our staff needs to treat storage refrigerators and freezers with care to ensure the integrity of seals and latches are maintained and that doors are not left partially or completely open during daily operations. 



Orientation of Temperature Controlled Equipment and Supplies
The number, type, and location of medical-grade refrigeration equipment should be determined by the nature and quantity of the products that will be stored therein. To gauge the number and size of units needed, we examine the projected quantity of reagents, calibrators, and controls we need to maintain our testing workload and the estimated cubic feet these products will occupy. In order to enable properly regulated and uniform temperature storage, we factor in the open space needed for sufficient air flow around the reagents and avoid overfilling any refrigerator or freezer. Storing refrigerated products in a neat, orderly way not only renders the different reagents readily accessible, but it also minimizes the need to leave doors open for excessive periods of time while searching for the needed product. Allowing ambient air into the refrigerated chamber for extended periods causes localized temperature changes and introduces the potential for partial defrosting of critical reagents. 

In order to avoid confusion, we place section-specific refrigerators and freezers near their respective sections in the laboratory. This enables expedient access and fosters a sense of ownership among the individual sections for maintaining constant temperature monitoring of their devices. This can be a challenge if sources of emergency power are limited, but we are fortunate to have a diverse distribution of emergency outlets in our laboratory.

Regulatory Concerns
The medical laboratories at IACH are accredited by CAP, The Joint Commission, the AABB, and the US FDA, as well as the Department of Defense Center for Clinical Laboratory Medicine. While each accrediting body has slightly different criteria for evaluating the effectiveness of temperature monitoring, they all address and require certain basic elements that cover the form, frequency, and documentation of monitoring; the calibration of monitoring equipment; and staff training and competency in monitoring. These are all equally critical but, as a CAP inspector, I often see deficiencies in the documentation of monitoring areas. A sound temperature-monitoring program, designed for a specific laboratory’s operations and unique requirements and constraints, and which follows rigorously enforced SOPs will enable compliance with whatever regulatory requirements you are bound by.

Assigning Responsibility and Procedure
Decentralizing responsibility for maintaining temperatures is the key to monitoring program success; all staff should be conscious and aware of any out of range conditions and should promptly take action, even if this simply means bringing it to the attention of a supervisor. From a general monitoring standpoint, each lab section should be responsible for the daily, weekly, and monthly checks of temperatures and monitoring equipment performance.

Per our alert protocol, if a duty tech (MT or MLT) notices that a refrigerator or freezer is out of range, the first step is to immediately determine whether it is a transient deviation (ie, the device has been left open while loading/unloading a large quantity of reagents or specimens). If so, the alarm is reset, the variation is documented, and the device is monitored until the temperature regains its proper range. Generally, these short variations are not troublesome, since they do not greatly affect the overall core temperature stability of the stored products. If the temperature breach is not due to stocking or removal, the duty tech will document the temperature variation, check the redundant monitoring device to make sure the problem is not simply a bad monitor, attempt to troubleshoot, and notify a supervisor of the variation. 

If one or more refrigerators or freezers are rendered inoperable, we have a contingency plan for relocating temperature sensitive products to other locations where they can be appropriately stored and monitored. In any case, we take temperature alerts seriously and document them correctly and completely; given that technology failures often happen slowly, such minor events can be a harbinger of more serious (or even catastrophic) temperature equipment failures in the near future.

Value of Temperature Data
The temperature monitoring data we maintain is reviewed each shift, daily, monthly, and retrospectively if trends indicate an issue has occurred or is likely to occur. Of course, any instrument QC data that is out of range without a ready explanation or resolution will trigger a review of the temperatures for both the monitoring instrument as well as the refrigerators and freezers that hold reagents and other products used in testing. 

In addition to regular data review, we also look for trends indicating a gradual shift upward or downward. These slow drifts demonstrate the gradual mechanical changes that might lead to an abrupt shutdown and out of range condition. We document all temperatures according to our SOP, which is written to comply with our various accrediting bodies as well as traditional good laboratory practices. The SOP spells out the requirement to document the temperature and to initial the entry, providing evidence that the temperature was actually taken. The section supervisor reviews our SOPs monthly and I, the chief medical technologist also conducts a monthly review. All temperature monitoring data is continuously available to our biomedical maintenance department as well as facilities engineering.

Gain Budget for Modern Temperature Monitoring
Traditionally, laboratory management has taken either a quality assurance or a cost effectiveness approach to the acquisition of modern temperature monitoring technology. Some also look to accrediting bodies and traditional good laboratory practices to stress the need for robust, continuous monitoring in order to comply with regulatory guidelines. Others will emphasize the value of active and passive monitoring in order to minimize losses incurred by ruined reagents, controls, and/or calibrator stocks and the additional increased expenses derived from repeating QC in order to compensate for these products becoming temperature stressed. All these approaches provide considerable positive evidence to support allocation of funds to acquire a progressive temperature monitoring system. However, the truest picture and the soundest approach is one that emphasizes the triangle of patient care—quality care, delivered in a timely fashion, and in the most cost efficient manner. By ensuring that reagents, controls, calibrators, and patient specimens are consistently maintained at the proper temperature—using a process that can be verified through positive monitoring methods—we are able to meet all three points of the triangle. The use of sound reagents and specimens has proven to provide the highest quality test results, and by keeping our instrumentation and on-board reagents constantly ready, we are able to produce accurate results in the shortest clinically possible time frames. 

Finally, these points support sound fiscal management by decreasing the time it takes to deliver care (and increasing patient throughput), reducing the potential for erroneous results (which can lead to adverse outcomes and legal issues), reducing the risk of readmissions (which might not be reimbursable under current guidelines), and reducing wasted staff time in both the pre-analytic and analytic phases of testing.

Conclusion
With health care’s increasing reliance on wireless systems, I envision a day when all refrigeration equipment is continuously and positively monitored, and deviations are automatically tracked. As the technology matures and accreditation bodies revisit their existing guidelines and regulations, we will come to rely more on continuous, positive monitoring for all our temperature sensitive materials. Ultimately, positive temperature monitoring helps ensure the highest quality patient care through accurate results and shortened turn-around times by reducing the need to prepare additional reagents and perform unnecessary QC and calibrations. While there are distinct costs involved in employing dedicated, medical-grade refrigeration equipment to seamlessly maintain tight temperature ranges, these are counter balanced by the benefits of always providing the best conditions for our reagents, controls and calibrators, patient samples, testing equipment, and the patients themselves.

The opinions and comments in this article are strictly those of the author and do not reflect the policies or opinions of the Department of Defense, the United States Army, or Irwin Army Community Hospital.


Joseph Keary, MS, MBA, is the chief medical technologist in the department of pathology at Irwin Army Community Hospital in Fort Riley, Kansas. He is also president of the Kansas City chapter of the Clinical Laboratory Management Association (CLMA) and the chair-elect of the CLMA Council of Chapter Leaders.

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