Confirmatory tests involve a battery of instrumental tests using techniques such as Gas Chromatograph-Mass Spectrometry (GC-MS) or infrared spectroscopy that separate individual compounds in the substance and positively identify the chemical signature of the illegal substance(s) within the material.
Which is an example of a confirmatory test?
Multiple confirmatory tests exist for both blood and semen. Confirmatory tests for blood include identification of blood cells under a microscope [Shaler, 2002], crystal tests such as the Teichman and Takayama tests [Shaler, 2002; Spalding, 2003], and ultraviolet absorption tests [Gaensslen, 1983].
Which is a confirmatory test for drugs?
Confirmation techniques other than GC/MS may be adequate for certain drugs of abuse, but GC/MS is generally accepted as the most rigorous confirmation technique for most drugs of abuse. It provides the best confirmatory information when performed appropriately.
Why is confirmatory test important?
Confirmation results that do not agree with the initial test results alert the laboratory to the possibility of a frame shift error so an investigation of the event can be initiated. The second purpose of confirmation testing is the use of a second (typically more specific) analytical methodology when available.
What are three presumptive blood tests?
Luminol, leuchomalachite green, phenolphthalein, Hemastix, Hemident, and Bluestar are all used as presumptive tests for blood.
What is meant by a confirmatory test?
Confirmatory test means a second analytical procedure to identify the presence of a specific drug or metabolite which is independent of the initial test and which uses a different technique and chemical principle from that of the initial test in order to ensure reliability and accuracy.
What is the difference between presumptive and confirmatory diagnosis?
Presumptive tests are less precise and indicate that an illegal substance may be present. Confirmatory tests provide a positive identification of the substance in question. … This is called qualitative analysis, and determines what substances are present and if one of more of those substances is illegal.
How accurate is drug confirm?
If the test results are negative, can you be sure that the person you tested did not abuse drugs? No. No drug test of this type is 100% accurate. There are several factors that can make the test results negative even though the person is abusing drugs.
What is the difference between a screening test and a confirmatory test for drugs?
15.3 Reporting test results – a screening test result shall be reported as negative or positive. A confirmatory test shall report the presence or absence and the identity of the drug/metabolite tested as well as its concentration.
What is the difference between a screening test and a diagnostic test?
Unlike a prenatal screening test, a diagnostic test is used to confirm the existence of a medical condition. Diagnostic tests will tell you and your doctor if, in fact, your baby has the specific condition you’ve tested for.
What is the confirmatory test for blood?
Confirmatory tests must be able to identify a substance with the lowest possible chances of a false positive. The confirmation that a substance is blood used to be addressed via the Takayama or Teichman tests, and from which species the blood originated was determined separately.
What does the phenolphthalein test tell you?
Phenolphthalein is a presumptive test that reacts with the heme molecule present in blood. A positive reaction gives a pink color. … The swab in the image below shows the characteristic color of a positive reaction with the phenolphthalein test, indicating the presence of blood.
What are the two presumptive tests that an investigator can do to check for the presence of blood?
- Phenolphthalein Test. Also known as the Kastle Meyer Test. …
- Luminol Test. How it works: A chemical compound, known as Luminol, is used in solution or sprayed onto suspected surfaces. …
- Alternative Light Sources.
What is the most common presumptive blood test done in the lab?
The Kastle–Meyer test is a presumptive blood test, first described in 1903, in which the chemical indicator phenolphthalein is used to detect the possible presence of hemoglobin.
What is a downfall of utilizing presumptive tests?
However, the disadvantage of many presumptive tests is that they show poor specificity to the human biological/chemical target [1,2] while touch DNA items often fail to produce a corresponding STR profile [3,4] due to low amounts of template material available on these items and/or PCR inhibition.