Modern Health Systems > Frequently Asked Questions 12 – What are Cut Off levels?
All drugs and healthcare tests have a cut off level. So what does this mean? The easiest way to think about cut off levels is to imagine a speed camera set to 30 mph in a built up area. Below 30 mph the camera wont respond, but above 30 mph the camera will flash. The cut off level is 30 miles per hour. The cut off level is the value at which a negative result becomes positive. Just as speed has units of miles per hour, medical test results also have units. In this section of the website we will refer mainly to drug tests, and a drug concentration is measured in nanogrammes per millilitre, or ng/ml. A nanogram is a thousand millionth of a gramme, or 0.000000001 gram. Why Do Tests Have a Cut Off Level? MHS tests are very sensitive. We could detect even the tiniest of traces of a drug in urine, saliva or hair, but the test would be too sensitive, because it would detect traces of environmental contaminants. It is estimated that 95% of banknotes, and most public toilets are contaminated wi
