Lab test results may be positive, negative or inconclusive, states WebMD. There are also what are called “false-positive” and “false negative” test results, notes WebMD.
A laboratory test is a procedure where a sample of blood, tissue, urine or other bodily fluid is examined for information about a person’s health. While some lab tests provide precise and reliable information on specific health problems, others provide general information that may assist in identifying or excluding possible health problems, states the National Cancer Institute. Positive lab results indicate that a substance or condition being tested for is found, or that a substance shows to be at levels higher or lower than normal, while negative results indicate that no substance or condition is present and inconclusive results are not clearly positive or negative, says WebMD.
False-positive test results show that a disease or condition is present when it is not present and a false-negative test result fails to detect a disease or condition when it is present, notes WebMD. Lab tests use a range to account for individual differences and factors that may affect these results may include sex, age and race, diet, medications one is taking and how well a patient follows pre-test instructions, states the National Institutes of Health.