How should controls be run to ensure the precision and accuracy of the reagent test strips used for the chemical analysis of urine?

How should controls be run to ensure the precision and accuracy of the reagent test strips used for the chemical analysis of urine?

• A. Positive controls should be run on a daily basis and negative controls when opening a new bottle of test strips.
• B. Positive and negative controls should be run when the test strips' expiration date is passed.
• C. Positive and negative controls should be run on a daily basis.
• D. Positive controls should be run on a daily basis and negative controls on a weekly basis

Answer: (C)

Running both positive and negative controls daily ensures the test strip system is functioning properly each day, supporting both accuracy and precision in results. A positive control shows that the strip chemistry reacts as expected when the analyte is present, confirming the assay can detect the target and produce the correct color change. A negative control confirms that, in the absence of the analyte, there is no unintended color development or background signal, guarding against false positives and ensuring the baseline is trustworthy. Daily checks catch day-to-day issues such as reagent degradation, improper storage, or reader drift before patient samples are tested. If you only run positives every day but schedule negatives only when opening a new bottle, you could miss days when the negative response drifts or when the system as a whole starts to fail, leading to inaccurate results. Waiting to perform controls until the expiration date also risks using strips that have degraded past their reliability. A weekly negative control, instead of daily, could allow undetected deviations to accumulate. Using both positive and negative controls every day is the most reliable way to verify that the strips remain accurate and precise in routine practice.

Running both positive and negative controls daily ensures the test strip system is functioning properly each day, supporting both accuracy and precision in results. A positive control shows that the strip chemistry reacts as expected when the analyte is present, confirming the assay can detect the target and produce the correct color change. A negative control confirms that, in the absence of the analyte, there is no unintended color development or background signal, guarding against false positives and ensuring the baseline is trustworthy. Daily checks catch day-to-day issues such as reagent degradation, improper storage, or reader drift before patient samples are tested.

If you only run positives every day but schedule negatives only when opening a new bottle, you could miss days when the negative response drifts or when the system as a whole starts to fail, leading to inaccurate results. Waiting to perform controls until the expiration date also risks using strips that have degraded past their reliability. A weekly negative control, instead of daily, could allow undetected deviations to accumulate.

Using both positive and negative controls every day is the most reliable way to verify that the strips remain accurate and precise in routine practice.