Being arrested for drunk driving in South Africa usually ends with a needle in your arm. Once the breathalyzer at the roadside or the police station reads over the legal limit, the matter shifts from an accusation into a forensic process, and the blood alcohol sample becomes the centre of the State’s case. How that sample is taken, stored, analysed, and put before the court is what the trial often turns on.
The procedure is governed by section 65 of the National Road Traffic Act 93 of 1996 and by the evidence rules in the Criminal Procedure Act 51 of 1977. Every step, from the time of arrest to the sealing of the sample kit, is regulated. Where the police, the nurse, or the laboratory slips outside those rules, the result can be challenged and sometimes excluded.
This article explains, in practical terms, what happens after a DUI arrest in South Africa: who may draw blood, why the time of driving matters, how the chain of custody works, what the forensic laboratory does with the sample, and how the accused’s right to a second test fits into the process.
The Legal Framework: Section 65 and the Power to Take Blood
Section 65 of the National Road Traffic Act 93 of 1996 creates two related offences. The first is driving while intoxicated by liquor or a drug having a narcotic effect. The second is driving, or occupying the driver’s seat with the engine running, while the concentration of alcohol in the blood or breath exceeds the prescribed limit. For an ordinary driver the limit is 0,05 grams of alcohol per 100 millilitres of blood; for a professional driver it is 0,02 grams per 100 millilitres.
Section 65(6) authorises a traffic officer who reasonably suspects that a driver has exceeded the limit to require that driver to submit to a blood test. The officer may then take the arrested person, or cause the person to be taken, to a medical practitioner or registered nurse for the sample to be drawn. The same section makes it an offence to refuse to cooperate, and section 65(5) allows a court to treat a refusal as prima facie evidence that the driver was over the limit.
The blood sample is not, on its own, a conviction. It is evidence that the State must lead through a witness, and it must be produced in court through the chain of custody established at the police station and the laboratory. A reading on a laboratory report never speaks for itself.
Who May Draw Blood, and How It Is Done
A blood sample in a DUI investigation may only be drawn by a medical practitioner or a registered nurse during DUI blood testing. A police officer is not permitted to take the sample. The sample is drawn into the official alcohol blood sample kit issued by the South African Police Service, which contains sealed, sterile vacutainers and a tamper-evident evidence container.
The person drawing the blood must record the date, the time the sample was taken, and the time of the alleged offence as supplied by the arresting officer. That time-of-driving record matters because the effects of alcohol absorption mean that alcohol continues to be absorbed and eliminated by the body over time. A reading taken an hour after driving does not, on its own, prove the concentration at the moment of driving. Where there is a gap, the State usually leads evidence from a forensic analyst who calculates a back-calculation using elimination rates.
After the sample is drawn, the nurse or doctor seals the kit, signs the seal, and hands it to the arresting officer together with the relevant SAPS form (commonly the J5). The seal and the signature on it are what later connects the vial in court to the person of the accused.
Time of Driving and the Two-Hour Window
The usefulness of a blood sample depends on how close it is taken to the moment of driving. As a practical matter the police aim to draw blood within roughly two hours of the alleged offence. The shorter the gap, the more directly the reading reflects the concentration while the accused was behind the wheel. The longer the gap, the more the State has to rely on expert inference and the more room there is for the defence to challenge the result.
Two timing records usually appear in the docket: the time of driving recorded by the arresting officer, and the time the blood was drawn recorded by the nurse or doctor. Where these times are missing, contradictory, or recorded after the fact, the reliability of the reading is put in issue. A criminal defence attorney will usually check both times against the arrest notification, the SAPS 73 register, and any CCTV or booking records from the police station.
The Chain of Custody
The chain of custody is the unbroken record of every person who handled the sample between the nurse who drew it and the analyst who tested it. In a properly run matter, every transfer is recorded on the SAPS exhibit register: who received the kit, when, where it was stored, and to whom it was passed next. The sealed kit should move from the officer to the exhibit store, from there to the laboratory, and finally to the analyst who breaks the seal.
A break in that chain is one of the most common grounds on which blood evidence is challenged. If a seal was broken at the station, if the kit was left unrefrigerated for days, if the same form was used to record two samples, or if a transfer is not signed for, the defence can argue that the sample tested in the laboratory may not be the sample taken from the accused. The court then has to decide whether the State has proved continuity beyond reasonable doubt.
- Seal intact on receipt. The analyst should record that the kit reached the laboratory with the original seal unbroken.
- Refrigerated storage. Blood alcohol samples degrade if kept warm. Long periods at room temperature can distort the reading.
- Signed transfers. Every handover should be initialled and dated on the exhibit label and the SAPS register.
- Single sample reference. The laboratory case number must match the J5 from the station, with no duplicate references.
Forensic Laboratory Analysis
The blood sample is analysed at an accredited forensic science laboratory, in practice the SAPS Forensic Science Laboratory. The analyst uses gas chromatography to measure the alcohol concentration in the sample and produces a certificate of result in terms of the Criminal Procedure Act. That certificate, when properly handed in, stands as prima facie evidence of the result, but it can be rebutted by the defence.
The analytical work itself is technical. The instrument must be calibrated, the controls must fall within tolerance, and the vials must be tested in a way that rules out contamination from the swab used to clean the skin. Where the laboratory’s own bench notes show deviations from procedure, the certificate can be put in question. The defence is entitled, through the docket, to obtain the analyst’s worksheets and not only the final certificate.
Backlogs at the laboratory mean that results often take many months, and sometimes more than a year, to be returned. Long delays do not automatically invalidate a result, but they can prejudice the accused’s right to a speedy trial and may, in serious matters, be raised under section 35 of the Constitution.
The Right to a Second or Independent Sample
When blood is drawn from an accused, the nurse or doctor will usually fill a second vacutainer at the same time. That second sample is preserved so that the defence can, if it chooses, arrange for an independent analysis. The accused is entitled to be told that a sample has been taken and to make arrangements, through an attorney, for the second vial to be tested at a private laboratory.
An independent result that differs materially from the State’s reading can support a challenge to the chain of custody, the calibration of the State instrument, or the analytical method used. Even where the independent result is consistent with the State’s, it confirms that the accused had a fair opportunity to test the evidence against them, which is itself a constitutional safeguard.
Where the second vial has not been preserved, or has been destroyed before the defence had a chance to test it, the court may be asked to draw an adverse inference against the State’s case. Preservation of the second sample is part of the duty to disclose and to keep evidence that may assist the defence.
How the Result Is Used in Court
In court the State leads the blood evidence through three categories of witness: the arresting officer, who identifies the accused and the time of driving; the nurse or doctor who drew the blood, who proves that the sample was taken from the accused and sealed; and the analyst, who proves the concentration measured. Each link has to be established, and each is open to cross-examination.
If all three links hold, the certificate of result is handed in as prima facie proof of the concentration. The evidential burden then shifts to the accused to raise a reasonable doubt, which may be done through the chain of custody, the analytical method, the timing, or the preservation of the second sample. If any link fails, the certificate may be excluded and the State is left to rely on observational evidence of the offence of driving under the influence.
The broader consequences of a blood-alcohol conviction are significant. They include a fine or imprisonment, a criminal record, and the endorsement or suspension of the accused’s driving licence, all serious consequences of driving offenses. Our practice sets out the penalties for driving under the influence of alcohol in more detail for readers who want to read further on sentencing.
Frequently Asked Questions
Who is allowed to draw blood for a DUI test in South Africa?
Only a medical practitioner or a registered nurse may draw blood under section 65 of the National Road Traffic Act 93 of 1996. A police officer is not permitted to take the sample. The sample is drawn into the official SAPS alcohol blood sample kit and sealed at the bedside.
How long after a DUI arrest can blood be drawn?
There is no fixed statutory cut-off, but the police aim to draw blood within about two hours of the alleged offence. The closer the sample is taken to the time of driving, the more directly it reflects the blood alcohol concentration at the relevant moment. Longer gaps require the State to rely on expert back-calculation.
How long do DUI blood test results take in South Africa?
Results from the SAPS Forensic Science Laboratory often take several months, and in some matters more than a year, because of laboratory backlogs. Long delays do not automatically invalidate a result, but they can affect the accused’s right to a speedy trial.
Can a DUI blood test be challenged in court?
Yes. The defence can challenge the time of driving, the identity of the person who drew the blood, the chain of custody, the calibration of the laboratory instrument, and the preservation of the second sample. Where any link in the chain fails, the certificate of result may be excluded.
Does the accused have the right to a second blood sample?
When blood is drawn, a second vacutainer is usually filled at the same time and preserved so the defence can arrange an independent analysis. If the second sample is not preserved, or is destroyed before the defence can test it, the court may be asked to draw an adverse inference against the State’s case.
What is the legal blood alcohol limit in South Africa?
Under section 65 of the National Road Traffic Act 93 of 1996, ordinary drivers may not exceed 0,05 grams of alcohol per 100 millilitres of blood. For professional drivers the limit is 0,02 grams per 100 millilitres.
Get help with a criminal law matter. If you have been arrested for drunk driving, or you are waiting on blood test results, the Criminal Law department at Otrebski Attorneys can examine the docket, the chain of custody, and the laboratory certificate, and advise you at every stage of the case. We are a 100% women-led firm, rated 5 stars across 12 reviews, with a Level 4 B-BBEE rating and a single Sandton office. Our Director, Nastasja Otrebski, leads the team that defends motorists across Gauteng and South Africa.
Disclaimer. This article is general information about South African criminal and road traffic law, not legal advice for a specific matter. Blood alcohol evidence, chain of custody, and sentencing outcomes depend on the facts of each case and on current court and laboratory practice. For advice about a particular charge, consult a qualified attorney or Legal Aid South Africa.