There are documented cases of maternal ingestion without in utero exposure. Lastly, some placentas can prevent some compounds from reaching the fetus.The screen only urine result is a clinically valid result, however, without an appropriate mass spectrometric confirmation, the urine result has no value in a forensic proceeding. The urine specimen was a screen only result and was not confirmed using an appropriate mass spectrometric method.There are many legitimate reasons for discrepant urine and umbilical cord results. Therefore, a negative result observed for the umbilical cord does not refute a positive result observed on the maternal urine specimen and the reverse is true as well. The result of any second collected specimen has no bearing on the validity of a first collected specimen. ![]() In this case, the donor has used that substance within the past three months, but may not have used it within the most recent three days. For example, a hair sample with a three month window of detection might test positive for a particular substance, while a urine sample from the same donor, with a 2-3 day window of detection, might test negative. The result of any second collected specimen has no bearing on the validity of a first collected specimen. Different sample matrices have different detection time frames.We recommend weighing the specimen on a jeweler’s scale. A clipping of 2-3 mm long (about the width of a quarter) from all ten fingernails will give about 100 mg of sample, the ideal amount for screening and confirmation. Fingernail samples are clipped and collected by the donor in front of a trained collection staff member. The time period during which drug or alcohol ingestion can be detected depends on the substance used, the amount used, and personal metabolism. Methods: Cross-sectional study of onychomycosis cases, analyzed by clipping and compared with data on normal nails and those with nail psoriasis. When drugs or alcohol are ingested, biomarkers can be found in nails as early as 1-2 weeks after. Environmental exposure to illicit substances can be detected immediately in nail samples. Biomarkers become locked in keratin fibers along the entire nail length and can be detected up to 3-6 months after drug or alcohol use. ![]() ![]() Fingernails are four times thicker than the typical strand of hair and often capture more substance than hair can. As the nail grows, substances can pass from the blood vessels below the nail into the keratin fibers, where they become trapped. Fingernails are made up of keratin, the same material that hair is made of. Highly stable, simple to collect, and easy to ship and store, fingernails provide a test sample at the cutting edge of drug and alcohol testing.
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