Milk analysis using milk analyzers in a standardized setting (MAMAS) study: A multicentre quality initiative

Abstract

Background: Human milk analyzers are increasingly used to rapidly measure the macronutrient content in breast milk for individual target fortification, to reduce the risk of postnatal growth restriction. However, many milk analyzers are used without calibration, validation or quality assurance. Aims: To investigate measurement quality between different human milk analyzers, to test whether accuracy and precision of devices can be improved by establishing individual calibration curves, and to assess long-term stability of measurements, following good clinical laboratory practice (GCLP). Methods: Sets of identical breast milk samples were sent to 13 participating centres in North America and Europe, for a total of 15 devices. The study included 3 sets of samples: A) initial assessment of the device's performance consisting of 10 calibration samples with random replicates; B) long term stability and quality control consisting of 2 batches of samples to be measured every time before the device is used, over 6 months; C) ring trial consisting of 2 samples to be measured monthly. The devices tested were Unity SpectraStar (n ¼ 5) and MIRIS Human Milk Analyzer (n ¼ 10). Results: There are significant variations in accuracy and precision between different milk analyzers' fat, protein and lactose measurements. However, the accuracy of measurements can be improved by establishing individual correction algorithms. Repeated measurements are more robust when coming from a larger batch volume. Long term stability also varies between devices. Conclusion:The variations in measurements between devices are clinically significant and would impact both daily dietary prescriptions, and the outcomes of clinical studies assessing the effect of targeted adjustment of nutrient intake in preterm babies. This study shows that it is crucial to follow GCLP when using milk analyzers to ensure proper measurement of macronutrients, similar to what is required of other medical devices.

What Are the Maternal Factors that Potentially Intervenes in the Nutritional Composition of Human Milk?

“…We measured the macronutrients (carbohydrate, protein and lipids) and total energy with the spectrophotometry technique, through INFRARED ANALYSIS using Miris Human Milk Analyzer™ (Miris AB, Uppsala, Sweden) (already validated for human milk analysis) following good clinical laboratory practice [ 15 , 16 ].…”

The Nutritional Composition and Energy Content of Donor Human Milk: A Systematic Review

“…The most common analytical method used for measuring macronutrients in the studies reviewed was infrared analysis. A growing body of evidence suggests that infrared analysis can reliably measure total nitrogen (e.g., crude protein) and fat in human milk, with appropriate sample handling and instrument calibration, though measurements of lactose were less accurate, and the measurement of total carbohydrates in human milk has not been validated (36)(37)(38)(39)(40)(41)(42) . None of the reviewed studies used reference methods suggested by the USDA (8) to measure total protein or total fat, and only 1 study used reference methods for measuring lactose, which limits the ability to draw conclusions about actual nutrient ranges.…”

Macronutrient Intake from Human Milk, Infant Growth, and Body Composition at Term Equivalent Age: A Longitudinal Study of Hospitalized Very Preterm Infants

“…We analyzed each sample of unfortified milk once. Performance testing of our analyzer in collaboration with the MAMAS study [24] revealed high accuracy (r = 0.99 true protein vs. elemental analysis, r = 0.98 fat vs. Mojonnier [25] and reliability (coefficient of variation 5.2% protein, 1.6% fat; email communication with Ms. Celia Kwan, February 2017). From 37 participating infants, we included nutrient data from 1626 milk samples.…”