Is there a large difference between batches of imported tumor marker reagents? Can we consider switching to Abbott

If considering switching to Abbott, a complete method comparison must be performed, not just a few samples. According to CLSI EP09-A3, at least 40 cases are required, covering low to high values, with particular emphasis on placing more samples near the cutoff values for AFP and CA125. Due to differences in antibody epitopes and reference standards for tumor markers, systematic bias may occur in results, and proportional error and constant error should be assessed through Bland-Altman or regression analysis. Carryover, limit of detection, and reference interval verification must also be performed. It is recommended to aliquot and retain serum samples and test them simultaneously on both instruments to reduce the effects of freeze-thaw. Only in this way can differences in results before and after the switch be clinically interpreted.

The difference between batches should be viewed on a project by project basis. The inter batch CV of AFP, CEA, CA125 imported from mainstream brands is usually stated as a lower range in the manufacturer's information, but the actual laboratory results are related to concentration levels, reagent batch numbers, and instrument maintenance. Suggest requesting Abbott and Roche to provide quality control data for at least three recent batch numbers, or directly request inter batch precision validation reports. Perform two levels of quality control continuously for 20 days, calculate the mean SD、CV， Combine the Westgard rule to see if there is drift. Don't change the system just based on one quality control float, first check whether the water quality, washing solution, substrate, and calibration sample are in the same batch.

For distributors placing orders, regular authorized suppliers typically have stock available in 2-4 weeks. For less common items, it may take 4-6 weeks or longer. It is recommended to require in the contract that stock be maintained for commonly used tumor markers. There is no uniform figure for how much more expensive they are compared to domestic products. Routine tumor markers such as AFP and CEA may be 30%-80% more expensive, while for CA125 and others it depends on packaging and negotiation. It is advisable to obtain quotes from both Abbott and Roche at the same time, and request that calibrators and controls be listed separately rather than bundled into the reagent pricing. You can ask the manufacturer to conduct a blinded comparison test on 10-20 clinical samples, and after evaluating concordance, then negotiate the price. This will give you more leverage.

The stability of bottle opening is crucial, especially 60-80 servings per day, which is not considered high. Large packaging reagents may result in waste that cannot be used up within the expiration date of bottle opening. Ask the manufacturer to provide onboard stability, storage temperature after bottle opening, calibration cycle, and calibration product shelf life. For example, some projects require frequent two-point calibration 14 or 30 days after bottle opening, which can increase costs. You can calculate the actual number of available tests for each kit based on the daily sample volume, combined with the number of days the bottle is opened, to determine the effective testing cost. Don't just look at the price of each test catalog, you need to package calibration products, quality control products, buffer solutions, reaction cups, and cleaning solutions for calculation.