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Abstract INTRODUCTION:
The increasing demand for sustainability and cost-efficiency in laboratories has prompted the development of innovative solutions that do not compromise analytical quality. In this context, we have tested concentrated LC-MS kits as an alternative to conventional, Ready-to-Use kits. These concentrated kits are designed to reduce shipping weight, packaging material, and storage volume, thereby supporting both environmental and economic goals. In addition to their ecological and logistical advantages, the kits provide enhanced flexibility, as all components are available individually or as part of starter and solvent kits, allowing for tailored usage and efficient inventory management. This study systematically evaluates the analytical equivalence of the new concentrated kits compared to their standard counterparts, focusing on a broad panel of relevant analytes.
METHODS:
A total of seven analytes were selected to represent a diverse range of compound classes, including water-soluble vitamins (Vitamin B1, B6), fat-soluble vitamins (Vitamin A, E), steroid hormones (cortisol, cortisone), and organic acid (methylmalonic acid).The method comparison was performed in accordance with CLSI guideline EP09-A3, using at least 40 samples to assess agreement between the two analytical methods.
Identical samples were analyzed in parallel using both the standard and the concentrated kits. For each analyte, method comparison was performed using linear regression analysis (slope, intercept, correlation coefficient R), estimation of mean bias, and assessment of precision through the standard deviation of differences. The evaluation focused on both the agreement of results and the practical interchangeability of the two kit formats. The concentrated format was also assessed for its impact on laboratory workflow, including ease of sample preparation, storage requirements, and potential for reducing shipping and packaging costs.
RESULTS:
The comparison revealed a consistently high correlation between the concentrated and standard kits for all analytes tested, with correlation coefficients (R) exceeding 0.98 and typically above 0.99. Regression slopes were close to unity, ranging from 0.98 to 1.14, indicating that the mean values obtained by both methods were highly comparable. The mean bias between the two methods was generally small relative to the respective measurement ranges, with no evidence of significant systematic deviations. For most analytes, the bias was less than 10 nmol/l (or equivalent), and the standard deviation of the differences was low, reflecting good precision and reproducibility. Notably, for cortisone, vitamin E, and MMA, the concentrated kits tended to yield slightly higher values (slope > 1.1), but these differences remained within acceptable limits and did not affect the overall analytical equivalence.
CONCLUSION:
The concentrated LC-MS kits demonstrate analytical equivalence to their standard counterparts across a diverse range of important analytes, delivering reliable, precise, and reproducible results. Beyond maintaining high analytical quality, the concentrated format offers many advantages in terms of sustainability, cost-effectiveness, and operational flexibility. These findings support the adoption of concentrated LC-MS kits as a robust, sustainable, and economical solution for modern laboratories, enabling both laboratory staff and purchasers to benefit from consistent performance, efficient processes, and a reduced environmental footprint. |
= Discovery stage. (53.14%, 2025)
= Translation stage. (22.33%, 2025)
= Clinically available. (24.53%, 2025)
