What are the required quality controls of a Miris instrument?

There are two required quality controls of the Miris instrument; the check procedure with zero-level adjustment, and a validation of the internal calibration.

The check procedure must be performed at start-up and after cleaning the instrument if continuing analysing samples. By doing a check, and an adjust when this is indicated on the instrument screen, the validity of the internal calibration is ensured by control of, and if necessary adjustment to, the correct zero-level.

As a daily control of the internal calibration, the instrument needs to be validated by analyzing a milk sample (replicate or reference sample) with known composition and compare the results to the established target values.

Do we need to adjust the instrument’s internal calibration after a period of use?

It might be possible that the instrument’s internal calibration needs to be adjusted after a period. To determine if this is necessary, the instrument regularly needs to be controlled by doing the check procedure with zero-level adjustment and a validation of the internal calibration using replicate samples or reference samples. Contact Miris (support@miris.se) or your local distributor if your instrument’s internal calibration doesn’t match with the established target values of the control sample.  

How do we get samples with known composition to control the instrument’s internal calibration?

Samples to control the instrument’s internal calibration can either be reference samples obtained from Miris, or produced by you as replicate samples. If you produce replicate samples Miris recommends to use standard milk reference methods (Fat – Röse-Gottlieb [ISO 1211], Protein – Kjeldahl [ISO 8968-1]. Carbohydrate content is calculated by difference from total solids – drying oven [ISO 6731]). Milk is a very complex fluid and the best approach is to use an accredited laboratory with personnel experienced in milk analysis.

The instrument shows different results compared to my replicate sample or reference sample control and I can rule out user errors (a non-zero set instrument, air bubbles and bad samples), how can I adjust that?

This must not be done without contacting Miris (support@miris.se).

Will the instrument detect air in the sample or if the milk is of poor quality? 

Most often yes, a message will appear on the display the meassage ”No energy in the system” or ”Air in the system ”.

How is the instrument’s internal calibration done?

The instrument is calibrated on a set of human milk samples with different contents of fat, protein and carbohydrate. These are analysed with chemical reference methods and the results are used for calculating the instrument’s internal calibration. The internal factory calibration of the HMA is optimized to measure human milk with normal biological variation.