Cape Town - The tests used to detect alcohol in the blood sample of musician Arno Carstens were accurate and standardised, the Cape Town Magistrate's Court heard on Wednesday.
Andy Hess, for the State, questioned State forensic analyst Pakama Pati on the setup of the laboratory and the gas chromatography used to distinguish every element in a substance.
Hess asked if the system was completely automated and if there was any chance of wrong calculations.
“The system is set up so you can actually see the calibration before proceeding with injecting the first sample,” Pati replied from the witness stand.
She said 10 percent of the results were manually checked for accuracy.
“We don't record each and every calculation we do. On the documents there should be a page where it shows calculations we do in order to check the results.”
Carstens was arrested nearly three years ago for allegedly driving under the influence of alcohol.
He has pleaded not guilty to a charge of drunk driving, alternatively driving with a blood-alcohol level of 0.20 percent.
The legal limit is 0.05 percent.
The defence had previously questioned why the alcohol reading was measured in milligrams and not millilitres as the standard for the National Metrology Institute of SA.
“We use the amount reflected in the initial page of the certificate supplied to us... it doesn't make a significant difference,” Pati replied.
“The alcohol content of the accused would still be 0.20 percent. The alcohol content wouldn't lower to, say, 0.05 (percent if measured in millilitres).”
Pati was excused from the stand.
A University of Pretoria doctor was expected to take the stand after lunch.
Sapa