Virus Specimen TTI

Time Temperature Indicator for virus testing kit transportation and storage

Timestrip VST TTI

Timestrip has developed the VST TTI – an exclusive smart label formulation which follows the time – temperature limitations of virus specimens under changing environmental conditions.

Global regulations require the use of a temperature-controlled transport systems to ensure the persistence of the virus viable within the specimen. The diagnosis of viral infections by culture relies on taking care in the collection and transportation of specimens.

Timestrip VST ( Virus Specimen Transport Range ) was developed based on published scientific data. It has been specifically formulated to provide a complete quality control resolution for proper transport and storage of clinical viral specimens. Timestrip VST TTI is a verified solution to indicate the required time limitations of both the cold and hot temperature conditions.

This unique, visual indicator, acts as a Time-Temperature Integrator (TTI) showing how the accumulated time-temperature history has affected the virus specimen during transport/storage. The chart below shows the Thermal Response of the VST TTI:

WHO Regulations

According to FDA & WHO regulations, coronavirus specimens may be stored/transported chilled between 2-8°C for up to 72 hours after collection.

In addition, virology specimen collection guideline similarly state that “most viruses remain stable at 4°C for 2-3 days“.

However, although viruses are highly stable at chilled temps, it was reported that when exposed to temperatures above 50-55°C coronavirus specimens become non-infectious within short timeframe (hours).

For more information

Guidance for laboratories shipping specimens to WHO reference laboratories that provide confirmatory testing for COVID-19 virus – Interim guidance 31 March 2020

Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens from Patients Under Investigation (PUIs) for Middle East Respiratory Syndrome Coronavirus (MERS-CoV) – Version 2.1

Timestrip VST (Virus Specimen Transport) series has been specially formulated to provide an adequate quality control resolution for proper transport/storage of clinical viral specimens.

What makes Timestrip VST unique?

  •  Our first integrating TTI indicator

  •  Created to adhere to WHO guidance on specimen transport

  •  Cost effective, irreversible single use indicator

  •  Unique serial number for optimal tracing

Timestrip VST offers a clear guidance of not only temperature abuse of a specimen, but how the cumulative length of time has effected the virus.

VST TTI provides a visual alert that the specimen’s stability may have been compromised. The VST TTI is created to assure you can quickly make decisions based on WHO guidance.

Timestrip VST TTI Range


  • time temperature integrator
  • reflects thermal history from chill to extreme hot temperatures


How VST TTI works

Simple technology – Effective results

The cumulative exposure to temperature over time is critical to the quality of the viral specimens. Our unique TTI indicator monitors the maximum allowed time of exposure to different temperatures, indicating whether the specimen samples are still viable.

Timestrip VST TTI offers a clear indication of temperature abuse, as well as the cumulative time of abuse that affect the virus in the specimen. The VST TTI provides a visual indication that the specimen stability may be impacted.

The VST TTI is created to enable you to quickly make decisions supported by WHO guidance.

The thermal response of the VST TTI indicator is shown in the table.

The “Indication of Time to Discard” is the total length of time the indicator will take to fill with colour, showing the specimen may no longer be viable.

Temperature Conditions Indication of Time to Discard
4°C 72 Hours WHO Accepted Limit
23°C 24 Hours
40°C 12 Hours
46°C 6 Hours
64°C 5 Hours Indication within a few hours
75°C 3.5 Hours

Timestrip VST TTI indicators are inert until activation.

Hold the indicator with your thumb on the button and push down firmly to activate.  A red line will fill in the first window, alerting you that the activation was successful.

Peel off the backing liner from the indicator and firmly adhere VST TTI label to the packaged clinical specimen. Ensure full adhesion to the specimen packaging.

Thermal Abuse

VST TTI label is designed to indicate, as per regulation, when 72 hours of chilled transport/storage have ended by showing a full red coloration of the indication window.

In case the transport/storage temperatures increase beyond the chilled recommendation, the label will show the visual discard indication sooner than 72 hours. When exposed to extreme hot temps (beyond 50-55°C) the label will show the visual discard indication within few hours, corresponding to reported virus’s stability periods at these temperatures.

Fully Red Window

Any full coloration of the indication window is a visual indication of a thermal exposure of the virus specimen.

Timestrip VST Technical Documents & Information



Type irreversible single use TTI
Temperature accuracy ± 1ºC
Time Accuracy ± 15 % in time under isothermal conditions
Splash proof Not suitable for immersion in water
Activation Type Inert until activated. Activation by button on top.
Color of progressing front Red
Storage Conditions Store indoors, at room temperature up to 30°C
Shelf Life 3 Years from date of manufacture (MD)


Frequently Asked Questions


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