In an assay, a control absorbance of 1.000 and a patient absorbance of 1.099 yields which result?

In an assay, a control absorbance of 1.000 and a patient absorbance of 1.099 yields which result?

• A. reactive
• B. nonreactive
• C. equivocal
• D. invalid

Answer: (A)

In this type of assay, the control establishes the baseline signal, and the patient’s absorbance is compared to that baseline to judge reactivity. A higher patient signal indicates a positive result because it shows a measurable response beyond background. Here, the patient’s absorbance (1.099) is greater than the control (1.000), so the result is considered reactive (positive). If the patient reading were lower, it would be nonreactive, and readings in a gray zone near the baseline could be equivocal. An invalid result would occur if the control were out of range or the assay failed.

In this type of assay, the control establishes the baseline signal, and the patient’s absorbance is compared to that baseline to judge reactivity. A higher patient signal indicates a positive result because it shows a measurable response beyond background. Here, the patient’s absorbance (1.099) is greater than the control (1.000), so the result is considered reactive (positive). If the patient reading were lower, it would be nonreactive, and readings in a gray zone near the baseline could be equivocal. An invalid result would occur if the control were out of range or the assay failed.