Liquid Nitrogen Monitoring of Reproductive Tissues - For Precious Cargo in LN2 Tanks, Failure is Not an Option

Liquid Nitrogen tank in a fertility clinic
Janice Bennett-Livingston
Industrial Measurements
Life Science

Last month was a wake-up call for cryogenic tank failures in fertility clinics in the US. Two separate medical centers storing reproductive tissues had failures in their Liquid Nitrogen tank monitoring. In one clinic, their initial estimate of 2,000 total affected eggs and embryos later doubled to over 4,000. Not only is this a devastating loss for clients, but the facilities must endure a very public catastrophe. In both cases, there was a remote alarm system on the storage tanks. In at least one case, the remote alarm may have been turned off.(At the bottom of this article relevant regulations and related reading.)

Although the root causes may be slightly different in each clinic, the solution for both would have been same: 

•        A remote alarm that sends alert to personnel regardless of time of day

•        Periodic alarm testing

•       Software that has user permissions to limit alarm configuration

•       Interface features that will not allow users to inadvertently disarm the system.

Both clinics are still investigating the incidents. But in a letter published by one fertility clinic it is clear that an alarm should have been sent and received. The letter states: "We don’t know who turned off the remote alarm nor do we know how long it was off, but it appears to have been off for a period of time." In one of the tank monitoring failures, the facility knew the tank was in need of preventative maintenance and was working with the manufacturer to troubleshoot the issue. Unfortunately, two problems arising at once is exactly why systems need to have safeguarding mechanisms that ensure no one can accidentally disable the alarm. 


viewLinc Remote Alarming

viewLinc Trend ReportIn many industries and applications an alarm being inadvertently disabled is not a rare occurrence. And it's double jeopardy when somehow an alarm is shut off and the equipment then starts to fail. That is why Vaisala's viewLinc Continuous Monitoring System has user access defined within the software, as well as processes that do not allow any user to simply disable an alarm by one single, quick click of a mouse.  The viewLinc software is designed so that users must walk through specific steps to disable alarms or make changes to configurations. Users must then annotate the action. viewLinc's audit trail shows exactly what was done in the system, by who, and when.  In one viewLinc application for monitoring human reproductive tissue, four facilities use Vaisala's HMT140 WiFi Data Logger that is equipped with LN2 temperature probes calibrated below -196° Celsius. Some HMT140s have a display and some do not, but all are equipped with a local alarm as well as the remote alarm sent to the software. Which is where the system's security in terms of user access really pays off.



viewLinc Audit TrailIn viewLinc, all events are recorded within a secure audit trail and displayed on the Events page where users can filter by monitored locations, user names, alarms, data transfers, and user notes. Any alarm within the system will be shown and information will include alarm status, duration, and any acknowledgments and comments that have been made. Alarm conditions displayed include high, low, open circuit, and communications loss. Each sensor can have up to eight different high or low conditions, ensuring that designated personnel are notified based on alarm severity or a standard escalation tree. Features like this are ideal for situations where you know that a chamber or LN2 tank may be having functional issues. Most viewLinc users set up their software's escalation and thresholds to match the needs of their application. The viewLinc software allows users to pause alarms, but only under certain conditions, and they must complete a process to do so. In other words, there is no "toggling" on and off of alarms. Alarms can be paused for predefined periods, allowing the user to turn off any sensor alarms during load cycles, or maintenance periods. After the pause time has been reached, the alarms will automatically re-enable for that sensor. All actions require the user to confirm identity and input comments.

Safeguarded 24/7

During facility off-hours, viewLinc sends alerts automatically via email, text, voice to multiple users to ensure each notification is responded to. Any alert can be configured to describe the alarm type, status, the threshold limits, and the current live value. If the alarm condition persists, the alert can repeat in user-selectable increments, indicating the current value of the sensor. For alarm acknowledgment, all users assigned to a given sensor can be notified that the alarm has been acknowledged, then notified again when the sensor value is back in the normal range. The software is designed to give a number of options for alarming.

What is not optional in viewLinc, is an alarm being disabled by anyone who can access the system. Users require the right permissions level and must go through actionable steps for final confirmation. The audit trail records every interaction. So if someone acknowledges the alarm and does not follow up, the system has recorded that.  The complaint we never hear about viewLinc (and probably never will) is that an alarm didn't go off, didn't send its message to the designated personnel, or the audit trail didn't record an interaction or event.  The software was designed with people and processes in mind; specifically busy human beings storing precious, invaluable materials where “failure is not an option.”

For more information on viewLinc monitoring of Liquid Nitrogen (LN2) temperature monitoring, read our Application Note:

Safeguarding Cryopreservation with Vaisala viewLinc


Related Reading


Reproductive tissue is regulated under section 361 of the Public Health Service (PHS Act). See: Guidance for Industry: Regulation of Human Cells, Tissues, and Cellular and Tissue-Based Products (HCT/Ps) - Small Entity Compliance Guide

Also: CFR Title 21 PART 1271 -Human Cells, Tissues, and Cellular and Tissue-based products (Subparts C and D)

"European Society of Human Reproduction and Embryology (ESHRE) guidelines for good practice in IVF laboratories"



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Jul 25, 2018
more information about the monitoring in LN2 Tank

Janice Bennett-Livingston

Jul 25, 2018
Thank you for commenting on our blog! To learn more about our solutions for monitoring and remote alarming in LN2 tanks, please see the viewLinc system:

And, our data loggers:

You can also contact our applications engineers:


Apr 19, 2019
I would like a liquid nitrogen level sensor (instead of a temp sensor), attached to the HMT140, to alert me when the level of LN2 falls below the probe. The probe would be suspended in LN2 and would only send an alarm when the probe is no longer in the liquid. Can you help?

Janice Bennett

Apr 23, 2019
Thank you for commenting!
Although Vaisala does not manufacture an actual “level sensor”, The HMT140 can monitor analog and contact signals from third party sensors. You would need to buy the LN2 level sensor – and then the signal goes to the HMT140 and gives an alarm for low levels. To learn more, please contact your local Vaisala application engineer - you can find them here:

hemant mahamuni

Jun 29, 2020
we have required cryogenic nitrogen ln2 tank monitoring & alarm system
pls send me price of system & manual

Janice Bennett-Livingston

Jun 30, 2020
Thank you for commenting! Yes, I will have the local sales person in your area reach out to you :)

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