الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 150 |  |  |
| | | from | 150 | | |
Abstract
Summary
Substances that are injected, inhaled or snorted bypass gastrointestinal absorption and are delivered immediately to tissues. Since many drugs are lipid soluble, they must undergo metabolism in the liver to render them water soluble which then allows them to be eliminated in urine. Blood and breath reflect moment-to-moment serum levels of an ingested substance, and offer the earliest and shortest windows of detection for substances. Sweat and saliva reflect the presence of a drug within the body several hours later. Urine offers a somewhat longer window of detection for substances, usually varying from one day after consumption to several weeks. Hair and meconium offer the longest windows of detection (weeks to months) .
Urine drug testing plays an important role in monitoring licit and illicit drug use for both medico-legal and clinical purposes. One of the major challenges of urine drug testing is adulteration, a practice involving manipulation of a urine specimen with chemical adulterants to produce a false negative test result. This problem is compounded by the number of easily obtained chemicals that can effectively adulterate a urine specimen.
In selecting the adulterants to investigate, we used three criteria. First, the dilution must not be the cause of the falsenegative results. Accordingly, the positive urine specimens were diluted 1:1 with isotonic saline and re-analyzed to verify that the diluted specimens remained positive. Second, the quantities of the interferents that cause falsenegative results must be small enough to be hidden on one’s person. If illicit drug users intended to adulterate their urine for the purpose of avoiding detection, they must avoid detection as they transport the interferent into the collection room. Third, the added interferent could not leave an obvious precipitate or residue in the urine specimen container, which would make the adulteration obvious. Typically, about 60 mL of urine is submitted to the drug-testing laboratory. Based on a 60-mL urine volume, the minimum amounts of the adulterants required to cause false-negative results ranged from 0.7 to 7.5 mL for the liquid interferents. However, the quantities of interferents required to alter drug testing results depend not only on the specific drug but also on the drug and metabolite concentrations, so individuals intent on adulterating their urine specimen.
This study showed that there was a highly statistical significant decrease of the PH after adulteration by vinegar at 10 and 40 concentration, there was a significant increase of the PH after addition of 10 concentration of visin and a highly significant increase after addition of 40 concentrationvisin and 10 & 40 concentration of Clorox but, after dilution with water the maximum increase of the PH was obtained after double dilution of water. And showed that the maximum significant decrease in the specific gravity was noticed in colorox at concentration 40 and double dilution of water (P-value<0.001).
Also showed that there was no effect of vinegar or visin at concentration 10 on urine creatinine level but the addition of clorox at concentration 10 or water had more effect on decresing the creatinine level significantly. Also at concentration 40 with vinegaracid, visin, Clorox and dilution with water there was more significant decrease of creatinine and the highest significance was demonstrated with double dilution of water followed by Clorox.
While ,It showed that there was no glucose detected in the urine samples before adding the adulterants at different concentrations or dilutions except in Clorox the glucose increased to 71.2 ±50.2 at 10 concentration and to 311.5 ±226.8 at 40 concentration (P-value<0.001).
This study also showed that there was no protein detected in the urine samples before adding the adulterants at different concentrations or dilutions except in Clorox the protein increased to 54.8 ±68.5at 10 concentration and to 54.8 ±68.5 at 40 concentration (P-value<0.001).And showed that there was no nitrates detected in the urine samples before adding the adulterants at different concentrations or dilutions except in Clorox the nitrates was detected in 76.7% of cases at 10 concentration and in 100% of cases at 40 concentration (P-value<0.001).
VIVA E auto analyzer shwoed the lower change in sensitivity and NPV than TLC and Accurate card.
Conclusions
The adulterants interfered somewhat differently with each of the drug assays. EIA assays for illicit drugs can be invalidated by specimen adulteration producing false-negative results. Therefore, if urine drug testing is to be conducted, pH, relative density, and appearance should be assessed and suspect specimens should be rejected. Not all adulterants can be detected, so observed collection is strongly recommended.
VIVA E auto analyzer shwoed the lower change in sensitivity and NPV than TLC and Accurate card.