Seventh, because the immune system is weak it cannot kill enough cancer cells and the cancer cells grow out of control. Thus, in summary, the root cause of cancer is microbes and parasites that are in the organs or colon (or bloodstream), which weakens the immune system. However, other things can cause cancer.
Test Reliability and Validity Defined Reliability. Test reliablility refers to the degree to which a test is consistent and stable in measuring what it is intended to measure. Most simply put, a test is reliable if it is consistent within itself and across time.
Specimen Validity Testing. As mentioned earlier, the federal urine drug-testing regulations contain provisions for MROs to review and evaluate drug test results where the test result is reported by the laboratory as adulterated, substituted or invalid.pecimen validity testing SVT is defined as the evaluation of a specimen to determine if it is consistent with normal human urine.