Musician Arno Carstens’ defence team has challenged forensic testing of blood samples for drunken driving cases.
|||Cape Town - Forensic laboratory analysts involved in the testing of blood samples in drunken driving cases “do their own thing” and ignore instructions contained in a blood-testing manual, the Cape Town Magistrate's Court heard on Thursday.
Analyst Pakama Pati testified in the drunk-driving case of Western Cape musician Arno Carstens, who has pleaded not guilty before magistrate Nadia Bonwari to a charge of drunken driving, and driving with a blood-alcohol level of 0.20 percent as the alternative charge.
The legal limit is 0.05 percent.
During Thursday's proceedings, Pati was cross-examined by defence attorney Milton de la Harpe, who focused on the level of care taken in the laboratory, and the reliability of Carstens' blood-alcohol count.
Carstens, the former Springbok Nude Girls frontman, was arrested in the Cape Town CBD in December 2010, when a traffic officer noticed his black Mercedes-Benz swerving.
It transpired during the proceedings that a solution specially prepared by the National Metreological Institute of SA, was used in the laboratory for blood-testing, and that personnel involved in the process, including Pati, had to carefully followed the instructions contained in a special manual.
De la Harpe told Pati that in his closing argument at the end of the case, he would call for Carstons' acquittal on the grounds that the analysis performed by her was unreliable.
“I will say that, due to careless practices in the laboratory, some of the blood used in a previous test contaminated my client's alcohol,” he said.
De la Harpe explained that a sealed container known as a standard, contained the solution specially prepared by the institute for blood-alcohol testing.
The contents of the sealed container lasted for a number of months, but once the seal had been broken, and the container opened, the solution only lasted for eight weeks.
It transpired that opened standards were sometimes used for blood testing, even after the eight-week period.
Pati admitted that she and other colleagues in the laboratory sometimes failed to comply with the instructions in the manual, and instead “do their own tests”.
At De la Harpe's request, the case was postponed to May 8, when defence expert Dr Neels Viljoen, retired head of the forensic laboratory in Pretoria, would attend the proceedings.
De la Harpe explained that Pati's cross-examination would become “extremely technical”, and for this reason he preferred Viljoen's presence.
He said his cross-examination had so far only dealt with two of eight technical aspects concerning the practices in the laboratory. - Sapa