Aside from urine as the widely used specimen of choice for testing of heroin, blood can also be used in heroin determination because as it may not stay that long in the blood long as in urine, it will rather give a good correlation between the level of drug and its pharmacologic deficiency in the body. Heroin stays in the blood up to 6hours.
Sample collection: A finger prick can be enough to use as a specimen sample but venipuncture may also be possible when further tests are needed.
Blood Drug Testing kits
Principle: The principle of blood testing in Heroin is much similar to the principle used in urine and oral fluid. The test device kit uses competitive binding immunoassay where competition happens with the drug and/or drug metabolites compete with the immobilized drug conjugate having limited antibody sites. The blood sample then binds with the labelled antibody-dye conjugate to form an antigen-antibody complex. Since there is an antigen-antibody complex, when it reach the test zone it will not produce any colored band when it exceeds the detection level. Continuing to the control zone, the unbound dye conjugate binds with the reagent giving a colored band indicating the validity of the test kit.
Interpretation of results:
Positive: Presence of colored band in the control zone and none in the test zone
Negative: Presence of colored band for both test and control zone
Invalid: Absence of colored band in the control zone even with or without the colored band in the test zone. Repetition of test is recommended.
Advantages:
- blood specimen will help detect particular amount or level of Heroin
- it serves as a specimen for early detection unlike others
Disadvantages:
- since Heroin can only be detected within 6hours in the blood, blood as a specimen of choice will give a false negative result if tested further time.
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