What on Earth is a UVC Dosimeter Card?

Healthcare professionals are well aware that medical environments face constant challenges from invisible threats such as Methicillin-resistant Staphylococcus aureus (MRSA) lurking on surfaces and in the air. These persistent risks have driven the development of advanced technologies like UVC robots and, more recently, dosimeters. But what exactly is a dosimeter, and how can it potentially enhance patient safety and improve infection control in healthcare settings?

Understanding Dosimeters

A dosimeter is a device used to measure exposure to a specific type of energy or radiation. In the context of healthcare facilities, UVC dosimeters are particularly important. These small, card-like devices change color when exposed to UVC light, providing visual confirmation that a surface has received an adequate dose of UVC radiation for effective disinfection [1].

The Silent Killer: Healthcare-Associated Infections (HAIs)

To understand the importance of UVC dosimeters, we must first grasp the gravity of healthcare-associated infections (HAIs). According to the Centers for Disease Control and Prevention (CDC), approximately 1 in 31 hospital patients has at least one HAI on any given day [2]. Even more alarming, these infections lead to an estimated 99,000 deaths each year in American hospitals alone [3].

UVC Disinfection: A Powerful Weapon

UVC light has emerged as a potent tool in the fight against HAIs. This short-wavelength ultraviolet light effectively inactivates bacteria, viruses, and other pathogens by damaging their DNA and RNA, rendering them unable to reproduce [4]. However, the effectiveness of UVC disinfection hinges on one critical factor: proper dosage.

How UVC Dosimeters Work

UVC dosimeters are placed in a room or area before a UV cycle begins. During the run cycle, the dosimeter changes color at various energy levels. The color change correlates to different doses of UV, or different levels of UV exposure at certain log reduction rates [1].

The center of the dosimeter contains photo-chromatic ink that changes color when stimulated by UVC radiation. Typically, the color changes from yellow to orange to pink based on the UVC dose received. It’s important to note that most dosimeters are designed to work with the traditional 254 nm wavelength and may not register properly with other UV sources like LED UVC, far-UVC, or pulsed-xenon UVC [1].

The Life-Saving Role of UVC Dosimeters

UVC dosimeters become literal lifesavers by offering several crucial benefits:

1. Validation: Dosimeters provide visual confirmation that surfaces have received the necessary UVC exposure to eliminate pathogens. 
2. Quality Assurance: They help ensure that UVC disinfection equipment is functioning correctly and delivering the required dose.
3. Optimization: Dosimeters allow healthcare facilities to fine-tune their disinfection protocols for maximum efficiency.
4. Safety: By confirming proper UVC exposure, dosimeters help prevent the spread of potentially life-threatening infections.
5. Commissioning New Fixtures: When setting up new UV-C fixtures, dosimeters ensure UV energy is hitting the intended surfaces.
6. Maintenance Alerts: By keeping a record of run cycles, dosimeters can indicate when it’s time to change a fixture or bulb due to decreased output.
7. Time Efficiency: Using dosimeters may help shorten disinfection cycles by showing when the desired level is reached, saving valuable time [1].

Types of UVC Dosimeter cards

Intellego Technologies offers a range of UVC dosimeters designed for various applications and UV-C wavelengths. Here’s an overview of the different types available:

1. TRI Card

• Size: 2.5″ x 3.5″
• Features: Center indicator (yellow) surrounded by three color references
• Measures: Accumulated dose in mJ/cm²
• Available for: 254 nm (LP Mercury Vapor) and 260-280 nm (UV-C LED)
• Variants: UVC254-TRI, UVCLED-TRI

2. TRI Check

• Size: 2.5″ x 3.5″
• Features: Larger indicator area (yellow) with three color references
• Measures: Accumulated dose in mJ/cm²
• Available for: 254 nm (LP Mercury Vapor)
• Variant: UVC254-TRI-CHK

3. Dots

• Size: 1″ adhesive dots
• Features: Indicate UV-C exposures at multiple levels
• Available for:
  • 254 nm & LED: 25, 50, 75, and 100 mJ/cm²
  • 222 nm: Peelable, adhesive dots on a 2.5″ x 3.5″ card
• Variants: UVC254-DOT, UVCLED-DOT, UVC222-DOT

4. Quick Check

• Size: 2″ x 2″
• Features: Center indicator revealing a check mark at 6 mJ/cm²
• Color references: 15 and 25 mJ/cm²
• Available for: 254 nm and UV-C LED
• Variants: UVC254-QCC, UVCLED-QCC

5. Personal UVC Exposure Indicator

• Size: 1″ octagon
• Feature: Reveals the word “STOP” when exposed to 6 mJ/cm²
• Purpose: Indicates Threshold Limit Value for safe occupational exposure
• Variant: UVC254-PIO

6. DUO Card

• Size: 2.5″ x 3.5″
• Features: Adhesive card indicating UV-C exposures at two levels
• Measures: 50 and 100 mJ/cm²
• Variant: UVC254-DUO

7. MRSA / C-diff Card

• Size: 2.5″ x 3.5″
• Features: Adhesive card indicating UV-C exposures for specific pathogens
• Purpose: Shows exposures that can achieve a 3-log reduction of MRSA and C-diff spores
• Variant: UVC254-MCD

8. UVC 1000 Dosimeters

• Size: 1″ Square
• Features: Visually indicate accumulated doses of 500 and 1,000 mJ/cm²
• Purpose: Suitable for decontamination of N95 masks
• Variant: UVC254-1JS

Conclusion

UVC dosimeters serve as a crucial line of defense, offering peace of mind to healthcare professionals and patients alike and ensuring that the disinfection capabilities of UVC light are harnessed to their full potential.

As we persist in combating HAIs and various infectious threats, UVC dosimeters will become increasingly essential in ensuring safer healthcare environments for everyone. These compact devices offer a straightforward yet effective way to verify UVC disinfection processes, potentially saving countless lives.

SOURCES

[1] Regency Insights. (2021). What is a UVC dosimeter? https://insights.regencysupply.com/what-is-a-uvc-dosimeter

[2] Centers for Disease Control and Prevention. (2023). Healthcare-associated Infections. https://www.cdc.gov/healthcare-associated-infections/php/data/?CDC_AAref_Val=https://www.cdc.gov/hai/data/index.html

[3] Magill, S.S., et al. (2014). Multistate point-prevalence survey of health care–associated infections. New England Journal of Medicine, 370(13), 1198-1208.

[4] Raeiszadeh, M., & Adeli, B. (2020). A Critical Review on Ultraviolet Disinfection Systems against COVID-19 Outbreak: Applicability, Validation, and Safety Considerations. ACS Photonics, 7(11), 2941-2951.