IVF Incubator Quality Control: Temperature, Gas and pH Checks That Protect Embryos

Embryos spend most of their time in the laboratory inside an incubator. Small, unnoticed changes in temperature, gas concentration or pH can affect development long before anyone sees a problem in the results. A disciplined incubator quality control routine is one of the most important habits of a well-run IVF lab.

Key takeaways

• Incubator displays must be checked against independent, calibrated instruments, not trusted on their own.
• Carbon dioxide level controls the pH of bicarbonate-buffered media and must match the media manufacturer's range.
• Many laboratories culture embryos at reduced (around 5%) oxygen.
• Fewer door openings, regular cleaning, working alarms and complete records keep conditions stable.

What an incubator controls

An IVF incubator maintains:

• Temperature close to 37°C
• Carbon dioxide, which sets the pH of bicarbonate-buffered culture media
• Oxygen, often reduced below atmospheric levels
• Humidity, in humidified models, to limit evaporation from culture drops

Benchtop incubators with separate chambers and larger box incubators are both widely used. Benchtop models recover faster after opening.

Daily checks

• Measure temperature with a calibrated thermometer placed where dishes sit
• Measure CO2 (and O2 if reduced) with a calibrated gas analyser
• Compare the readings with the incubator display and record both
• Check gas cylinder pressures and automatic changeover

pH checks

The pH of culture medium depends on the CO2 setting. Laboratories check pH periodically, especially when changing media lots or incubator settings, and adjust CO2 to keep pH within the manufacturer's recommended range.

Reduced oxygen

Many IVF laboratories culture embryos at around 5% oxygen, closer to conditions in the reproductive tract. Reviews suggest this may improve outcomes, although the strength of the evidence is limited.

Stability habits

• Limit and plan door openings
• Allocate chambers by patient where possible
• Clean with embryo-safe, low-VOC agents on a schedule
• Keep alarms active and tested, with a clear out-of-hours response plan

Records and audits

Every check, deviation and corrective action should be logged. These records support internal quality review and the record-keeping duties of the ART (Regulation) Act 2021 and Rules 2022.

Bringing a new incubator into use

Before a new or repaired incubator is used for patients, it should be validated. Run it for a period with no embryos while checking temperature, gas levels and recovery after door openings against independent instruments. Many laboratories also run a biological quality test, such as a sperm survival assay, before clinical use. Record the validation and keep it with the equipment file.

Frequently asked questions

How often should incubators be calibrated?

Daily checks against independent instruments, with formal calibration at the intervals set by the manufacturer and the laboratory's quality system.

What should happen if an incubator fails?

Follow the laboratory's contingency SOP: move dishes to a validated backup incubator, record the event and review any affected cycles.

Are benchtop incubators better than box incubators?

Both are used successfully. Benchtop models recover conditions faster, while box models hold more dishes. Many labs use both.

Build lab quality skills at ReproNest

ReproNest's IVF Lab Management Course covers incubator QC, calibration, gas management and audit readiness. Read our guide to IVF lab KPIs, or contact us.

This article is educational content for healthcare professionals and trainees. It is not medical advice and does not replace clinical judgement, current guidelines or the ART (Regulation) Act 2021 and Rules 2022.