What color will the nitro zone test fluid turn when a positive result is indicated?

The nitro zone test is used to identify the presence of nitroglycerin and other nitrates in various samples. When a positive result is obtained during this test, the test fluid will typically change to a blue color. This color change indicates that nitrates are present in the sample being tested. Understanding the significance of this color shift is crucial, as it helps in diagnosing conditions related to nitroglycerin use, particularly in emergency medical situations. Knowing this can significantly aid responders in evaluating a patient's condition and determining the necessary course of action based on the presence of nitrates.