Some diagnostic tests rely on a color change to indicate the result. A person who is color blind may have difficulty reading the result. This can cause a delay in diagnosis or a failure to adjust therapy appropriately.


Example of common tests using a color change:

(1) urine dipstick

(2) Clinitest for urinary reducing substances


People with problems in color vision:

(1) hereditary color blindness

(2) acquired color blindness

(2a) diabetes mellitus (typically a blue-yellow defect)

(2b) retinitis pigmentosa

(2c) toxic retinopathy


Mitigating the adverse effects:

(1) Screen a person for color blindness as part of the test orientation and periodically thereafter if the person has a progressive disease.

(2) Determine the severity of the color blindness and the colors affected.

(3) Read the test in a bright light (associated with fewer errors than if read in dim light).

(4) Have a non-color blind person read the reaction.

(5) Have a machine read the reaction.

(6) Select a detection system with a color within the person's visual range.


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