by Henk Botha FIAC B.IUR. LL.B
© Bellstone
Training (International) Limited
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This report describes South African law.
1.1 Only medical staff may do the direct venous bloodalcohol test.
1.2 Usually this test is reliable. But when the test takes place within 30 and 60 minutes of the last drink, the test is unreliable. The reason for this is that the arterial and venous blood distribution differs in terms of time. Arterial blood distribution always takes place faster than venous blood distribution. Intoxication occurs when arterial blood with alcohol reaches the brain. Blood is usually drawn from the veins and not the arteries. While the body still absorbs the alcohol, there would therefore be less alcohol in the blood than in the arterial blood that goes straight to the brain.
1.3 The lungs receive a great deal of arterial blood. Consequently, a breathalyser test may be more accurate during the absorption phase of alcohol. An employee who has been drinking shortly before the test, may test negatively with a bloodalcohol test, but positive with a breathalyser test.
2.1 Security officers, managers, supervisors and human resources officers may use breathalyser tests.
2.1.1 The electronic breathalyser is the most accurate, and may even be more accurate than a bloodalcohol test. However, it must regularly be calibrated to ensure accuracy. If regularly calibrated, its margin of error is between 5 and 7%. If an employee fails the breathalyser test and if you have facilities for a bloodalcohol test, give him or her the choice to take that test. But wait about 30 minutes after the breathalyser test before taking a blood sample. This is to allow for the proper alcohol distribution from the arteries to the veins.
2.1.2 The alcolyser is another apparatus for testing alcohol in the blood. However, its margin of error is at least 25%. It is therefore advisable to avoid this apparatus.
3.1 Security officers, managers, supervisors and human resources officers may use urine testing.
3.1.1 There is a dipstick test, but it is unreliable as to quantity of alcohol. It only can show the presence of alcohol in the urine. You can use it to screen employees.
3.1.2 The more accurate tests are known as the head space gas chromatography, and enzymatic biochemical procedures.
3.1.3 During the alcohol absorption phase, this results of this type of test will be lower than the results of the breathalyser test and the bloodalcohol test.
3.1.4 One should not use the first urine sample because it may have been in the bladder for some time.
4.1 Security officers, managers, supervisors and human resources officers may use saliva testing.
4.1.1 There is a dipstick test, but it is unreliable as to quantity of alcohol. It only can show the presence of alcohol in the saliva.
4.1.2 You can use it to screen employees.
1.1 This type of testing involves measuring the effects of alcohol on the body and medical staff should carry it out.
1.1.1 These tests are useful to identify alcohol problems.
1.1.2 These tests are known as the Gamma glutamyl transferase (GGT), Mean corpuscular volume (MCV), uric acid and triglycerides. Consult medical staff about these tests to identify progressive problems.
1.2 You can also get reliable evidence about a person's intoxication by simple observation. You may observe signs of drunkenness, such as:
smell
Ensure that you have witnesses who can independently observe the person.