Urine Strips

Although Ascorbic Acid (Vitamin C) in urine is not an indicator of disease, it's presence interferes with strip tests for glucose, blood, nitrite and bilirubin, giving rise to falsely low or negative results.

Excess vitamin c is excreted in the urine and concentrations capable of causing interference may be reached after ingestion of fruit, or a glass of fruit juice. We can safely say that most people taking supplements, etc, will produce in excess of 80mg/dl of ascorbic acid where 40mg is a very small amount, a glass of orange juice for example, but this varies from person to person.

Having been involved in the diagnostic market for over 25 years and have had first-hand experience in recent MRHA trails on urine strips, we know there are huge variances in quality between different makes of strips. Less than six months ago we commissioned an independent study via WEQAS (Welch External Quality Assurance Laboratory) who looked in to vitamin c interference on a range of strips, that we believe are sold more on price rather than quality.

Unfortunately because of legal issues we are not able to name the competitors products in question, but check your strips product information to see if any references are made to how Ascorbic Acid (Vitamin C) interfers with the test results.

Our Screen-Test branded test strips are not affected by Ascorbic Acid (Vitamin C), so you always get results you can rely on.