Basic Guide To Drug Tests

A drug test is an investigative method for determining the type and amount of ingestion of a drug or drug in the body of a human or animal. A drug test is usually carried out due to a suspected abuse. The drug screening test comes in different types, including urine, hair, blood and saliva screening.

The urine screening test can take the form of a simple strip to immerse in a urine sample, a case containing a test strip to be immersed in a urine sample or a cassette on which are deposited some drops of urine through a pipette. The salivary test consists of a test box (integrated box or cassette-type test) and a swab stick for saliva collection.

Immunological preliminary tests

To rationalize the examinations, the samples can be subjected to an immunochemical preliminary test with a lateral flow test. Thus, samples can be preselected quickly, sensitively and without major treatment for the presence of various active substances or active ingredient classes. For this purpose, the principle of cross-reactivity is used, so that a test can be used to test an entire group of substances.

Immunological testing has its origins in the North America, where drug-detection immunoassays since the late 1980s, in addition to their use in toxicology, have been widely used in testing job candidates or drug-free workplace surveillance (workplace testing) are used.

As a result, many manufacturers of immunoassays, when specifying the decision boundaries between positive and negative (cut-off values) according to specific criteria, that is H. the requirements of the NIDA. For many years, however, more sensitive tests with lower cut-offs have been offered. In some cases, the cut-offs are legally prescribed, usually, they are determined by the test manufacturers.

All assays are based on the principle of the antigen-antibody reaction, according to which the desired substances compete with antigens for the binding with specific antibodies. The number of immune complexes formed from antibodies allows a statement about the concentration of the matter in the sample.

However, antibody-antigen binding is not directly analytically accessible in most immunoassays. This problem is solved by coupling one of the two components, the antigen or the antibody, with a well-detectable label substance. As with an enzyme (biocatalyst), dye, fluorophore or more rarely with a radioactive component.

Period of detection

The detection periods for each substance vary depending on the nature of screening test conducted in a workplace. The duration may vary according to a wide variety of factors, including the frequency of consumption, the user's weight, metabolism, quantity, age, weight and state of health of the user. For convenience, the metabolite detection period is incorporated with their respective drugs in the table.

For example, drugs like cocaine are detectable several hours after ingestion, yet their metabolites stay in the system several days and can detect through urine screening. In this case, it is the longest detection period (that of the metabolites).

The tests performed on saliva are identical to those performed in the blood, with the exception of THC. A salivary test can detect a drug very early (minutes after consumption). Since urine cannot detect very recent drug use, it takes a minimum of six to eight hours between consumption and the completion of the urine test for detection to be possible. For hair, the minimum is two weeks and for sweat seven days.

Immunoassays

There are two main types of drug immunoassays: test strips (sticks) or test cassettes for rapid, manual on-site detection (rapid drug tests / POCT) and automated liquid reagent tests, most of which are performed in laboratories (often referred to as "EIA" abbreviated, but there are many other names that are often brand names, such as CEDIA, KIMS, Syva, etc.).

EIAs often provide a lower cut-off compared to test strips/cassettes, that is, smaller quantities can be detected. Above all, however, reading errors - the most common source of error in test strips are virtually eliminated by automated measurement, and EIAs have much higher precision and accuracy.

In addition to urine testing, immunoassays can also be used to detect drugs in other body materials. Thus, EIAs and microtiter plate tests on the market, the enzyme-immunochemically very sensitive to the detection of drugs or metabolites z. B. in whole blood or serum.

An evidence-proof quantitative determination of the various drugs from a complex matrix, such as the serum requires the use of a selective method. The low concentrations in the nanogram range. More information drug tests can be read on http://passhairfollicledrugtest.com.