Limit Tests

GOOD VALIDATION PRACTICE (cGVP) LABORATORY, METHOD AND ANALYTICAL VALIDATION
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Hi All
I’m hoping you can help. The USP outlines the required elements for validating a Limit Test as specificity & detection limit. However it also states that Range may be required in some instances, depending on the specific nature of the test.

The definition for range is the interval between the upper and lower levels of analyte (including these levels) that have been demonstrated to be determined with a suitable level of precision, accuracy, and linearity.

Can you clarify how I’d determine range for a Limit Test if I’m only required to look for specificity & detection limit (or do I need validate precision, accuracy, and linearity in addition?)

Thanks for your help.

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In fact, the different requirements in USP with that in ICH Q2 include two items (ACCURACY and RANGE). They are both unnecessary in ICH but “maybe” required in USP.
A typical limit test is TLC.
I can understand why RANGE is required inh USP, since only in certain range, the colorimetry is valid.
But I’m not sure for the accuracy.Does that mean, let’s say, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% the five concentrations can be differentiated, then the deviation for accuracy is not more than 0.1% and the range is 0.1%~0.5%?
Any comments would be appreciated.

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[quote=gallacg]Hi All
I’m hoping you can help. The USP outlines the required elements for validating a Limit Test as specificity & detection limit. However it also states that Range may be required in some instances, depending on the specific nature of the test.

The definition for range is the interval between the upper and lower levels of analyte (including these levels) that have been demonstrated to be determined with a suitable level of precision, accuracy, and linearity.

Can you clarify how I’d determine range for a Limit Test if I’m only required to look for specificity & detection limit (or do I need validate precision, accuracy, and linearity in addition?)

Thanks for your help.[/quote]

Hi,

Limit test for control impureties required to be validated using specificity and detection limit while quantitative tests are validated with all parameters.