Bioequivalence and Bioavailability Forum

Dear Najat,

❝ Dear Sir

We also have some Ladies on the forum, don't discourage them from answering

❝ LC-MSMS generated software calculations printout (Waters API 3000)

Which software ? Waters' is Masslynx, API 3000 runs with Analyst.

❝ Where discrepancy between manual calculation and LC-MSMS generated software

❝ calculations printout (Waters API 3000) gave two different results,

This may happen due to rounding. How many digits do you use for manual calculations ? Not just decimals (1.2 is one decimal but 2 digits, 123456.7 is still one decimal but 7 digits, 0,00005 is 5 decimals but 1 digit). If you use 3 digits for calculations and give the result with 4 digits, you'll get in trouble. The software will use more digits than what you get on the printout.

❝ Kindly advice what action(s)/step(s) should be taken to solve this

❝ dilemma? And how do you solve such a discrepancy in results?

Try and get enough digits on the printout (or on screen)... In most software the user can define at least the number of decimals in the output.

❝ And how would European authorities look at such a case ?

Assessors will probably not recalculate. Some inspectors might. Some definitely will. But these ones are supposed to know about rounding. And that's something you can at least try and explain.

Regards
Ohlbe