Drug Testing - Urine Constituents

Urinalysis is one of the most powerful diagnostic tools used in the medical field today. Hundreds of tests can be performed on individual urine to determine the condition of the donor. Urine contains thousands of different types of compounds. It is literally the aqueous trash of the body. A cup of coffee has over ten thousand compounds alone. Drug testing laboratories have narrowed the choice down to two or three tests for determination of a suitable sample. If the urine sample falls out of the parameters the sample will be labeled "too dilute, unsuitable, or adulterated" depending on which parameter is incorrect.

pH - is a relative measure of acidity or basically, with a range of 0-14. In the middle is 7.0 which is considered neutral. Acids have low pHs usually less than 1. Bases, such as bleach have high pHs around 10.5. Urine samples must have a pH in the range of 4.5 - 9.0. Both acids and bases will destroy drug metabolites, so the labs check to see if any are present. If a chemical additive is used, it should leave the pH relatively unchanged, within the 4.5 - 9.0 ranges.

Specific Gravity (SG) - is a fancy word for density. Simply drinking tons of water can fool a drug test. By measuring the SG a lab can detect if the donor is trying to beat a drug test by dilution. If the sample is too dilute, the SG of the urine sample will be below 1.005 g/ml. A lab result like this might come back as inclusive; test not performed, or sample too dilute. It is against the law to fail an individual for providing sample(s) which are too dilute. On the flip side of the coin is high density. If a sample has a density above 1.020 g/ml, then an additive has been used. It is considered proof of adulteration if the SG is at this level and is legal to fail an individual for having a SG above 1.020 g/ml.

Creatinine - is a measure of kidney functions to determine how dilute or concentrated a urine sample is. The creatinine has to be below 20 mg/dl for the sample to be considered too dilute. Creatinine levels above the 20 mg/dl are considered acceptable.

Creatinine is found in all muscle tissue and originally begins as creatine. Creatine passes through the body in two ways. First is consumption as it is found in all types of meat. The second is production by the body. As muscles are broken down and rebuilt creatine is converted creatinine. Creatinine in high levels is toxic, and so the kidneys filter out the creatinine from the blood and pass it on to the bladder. Creatinine extraction from the blood is at a very constant rate and the level in the urine is constant varying only with the length between urinations. Therefore creatinine levels less than 20 mg/dl indicate a bladder which is continually being emptied in an attempt to pass a drug test.

Labs sometimes look at other constituents of urine with a ten-panel dipstick called a multistick. The ten tests on the multistick are:

Leukocytes Leukocytes Urobilinogen Protein pH
Blood Specific Gravity Ketone Bilirubin Glucose