Arsenic poisoning is an uncommon condition where the levels of naturally occurring arsenic in the human body rise to toxic levels. This leads to severe medical complications, including several types of cancer, hair loss, gastrointestinal disorders, and skin abnormalities. Long-term exposure to low levels of arsenic or a short-term, high-level exposure can lead to bleeding from internal organs, coma, and finally death. A few hundred years ago, arsenic was a popular ingredient of many medicines and cosmetic products, since its toxic effects were not understood. It was also a popular homicide tool until the 19th century, since it is odorless, tasteless, and very toxic. However, the advent of reliable testing methods has made it less popular among the criminal class. However, many people still suffer from accidental arsenic poisoning, mainly due to contaminated drinking water or hazardous work environments. While normal levels of arsenic can be processed by our bodies, excess amounts are secreted in urine or stored in keratin-based tissues such as hair and nails.
The urine test for arsenic is one of the most reliable methods to check for abnormal levels of arsenic in an individual. Arsenic in urine is also a combination of both organic and inorganic types, where the organic is consumed in the normal diet. The toxic effects of arsenic are caused by the inorganic type, which can be separately identified in the arsenic urine test. Methods used to test hair and nails for arsenic are less reliable, mainly due to the risk of samples being contaminated by environmental pollution.
For accurate results, most laboratories conduct the urine test for arsenic using samples collected over a period of one or two days. This provides a clearer picture of how much arsenic is absorbed and processed by the body. In some instances, patients may be required to avoid shellfish for a few days, to avoid trace elements of arsenic present in the food.
Once the urine sample is collected, there are several laboratory methods to test for levels of arsenic. Many of these can separate the various types of organic and inorganic arsenic by identifying certain metabolies such as methylarsonic acid (MMA) and dimethylarsenic acid (DMA). The final results are expressed purely in terms of the toxic inorganic arsenic. The normal levels in the arsenic urine test conducted over a 24-hour period should not be more than 50 mcg in healthy adults.