Dear Karolina,

I am assuming that your method is validated under repeatability conditions, which means same laboratory, same analyst, same equipment, in a short period of time. You can estimate the same figures of merit that you estimated for the previous validation using the old and the new equipment. In the statistical analysis you should include the equipment as a factor.

I would suggest a validation study under intermediate precision conditions, which means: different analysts, a higher period of time (several non-consecutive days), and different equipment. It is better to use a certified reference material. The resulting relative figures of merit can be compared with those reported in collaborative studies, i.e. under reproducibility conditions.

In order to see if the new equipment is consistent, you would only need to perform several runs with the same material in the new equipment, several analysts, in several non-consecutive days, and calculate the figures of merit. Then, you can calculate the relative figures of merit and compare them to the obtained with the estimated using the old equipment.

I recommend our article published in Accreditation and Quality Assurance

https://www.researchgate.net/publication/281639526_Overcoming_constraints_of_the_control_charting_approach_for_measurement_uncertainty_assessments

https://link.springer.com/article/10.1007/s00769-015-1161-0

I recommend the journal to assess the quality of analytical results in several fields (including molecular biology).

Best wishes,

Amaury

You do not need to validate it fully if it has already been done. Partial validation will work. However, accuracy, precision and repeatability should be checked

Dear Amaury Borges Miranda,

Thank you very much for your answer!

What if I do not have the entire validation procedure from the first equipment? I have the method itself, which we use and which was validated by the head company. And now to streamline our work we decided to invest in a second equipment and we wanted to transfer the method to the new equipment ourselves. Is this possible? Without a validation procedure, are we not able to do it?

Hi Dear Dr. Karolina Furtak,

Greetings of the day,

You could use a reference gene and standardized and well-known amplification conditions for that target (denaturation temperatures, primer ringing, and extension of the target DNA strand). At the end of repeated amplification cycles, you have an amplicon amount. This test must be performed on both equipments (old and new). Use known concentrations of the target DNA (if possible make some solutions and quantify in Qubit). After amplification confirms the size of the fragment on an agarose gel. Then set up an essay on Qubit to quantify the PCR product (amplicon). Then build efficiency curves (X-axis = target DNA concentration and Y-axis = amplicon concentration). Calculate the R of the curve fit and compare it to the data from the old thermal cycler and the new thermal cycler.

This must be done for each protocol to be validated (conventional thermal cycler).

If you are a qPCR thermal cycler, build standard curves for the target genes and observe the melting curve on both devices. Also, check the adjusted R for the standard curves.

Dear Karolina,

It is possible to transfer the method from the old to the new equipment even if you do not have fully validated the method in the old one. However, I would recommend a full validation using both equipments, i.e. under intermediate precision conditions. It is even more important for accreditation purposes. The main figures to estimate must be systematic error and measurement uncertainty. I don´t know if the scientific community in your field have defined a target measurement uncertainty value, i.e. under reproducibility conditions. I agree with the comment from Adijailton Jose de Souza. He explained the validation with the specific terms of the PCR test. I liked it because I saw in his answer the principles I explained you in more general terms, although I am not an expert on this.

Thank you Dear Amaury Borges Miranda for your comment.

In our laboratory routine, we always work with periodically calibrated equipment. Protocol validation and optimization steps are always necessary. Mainly because sometimes we are unable to buy reagents of the same brand that we often use (due to lack of stock). So whenever there is a change in the PCR reagents, we have to optimize the protocols and check the amplification fidelity of the gene with those new reagents.

Dear Adijailton Jose de Souza and Amaury Borges Miranda,

Thank you very much for your comments!

I didn't know how to do this before, but thanks to you I at least have some idea now.

Greetings,

Karolina