A qualitative drug screen is used to detect the presence of a drug in the body. A blood or urine sample may be used. However, urine is the best specimen for broad qualitative screening, as blood is relatively insensitive for many common drugs, including psychotropic agents, opioids, and stimulants. Common methods of drug analysis include chromatography, immunoassay, chemical (spot) tests, and spectrometry.
Polycythemia Vera Complications. If you have PV, the thickness of your blood and the slowed blood flow can cause serious health problems. Blood clots are the most serious complication of PV. Blood clots can cause a heart attack or stroke. They also can cause your liver and spleen to enlarge.
1 Polycythemia vera (PV) is related to a genetic mutation in the JAK2 gene, which is thought to increase the sensitivity of bone marrow cells to Epo, resulting in increased red blood cell production. 2  Levels of other types of blood cells (white blood cells and platelets) are also often increased in this condition.