Entrance

In criminal proceedings, proof of drug use often biological evidence . Blood and urine tests, in particular, are the primary methods for determining whether a person has used drugs. However, these tests are only for the duration the substance can be detected in the body . Therefore, the question of how long the drug remains in the blood and urine is critically important in both the investigation and prosecution phases.

Detection times vary depending on the type of drug, frequency of use, individual metabolic characteristics, and the testing methods used. This article will examine in detail the detection times of different types of drugs in biological samples and their legal evidentiary value

---

Factors Determining the Detection Time

How long a drug can be detected in blood or urine depends on the following factors:

• Type of drug (marijuana, cocaine, amphetamine, heroin, MDMA, etc.),

• Method and frequency of use (there is a difference between single use and dependent, continuous use),

• Personal characteristics (age, weight, body fat percentage, liver and kidney function, metabolic rate),

• The test methods used by the laboratory (advanced tests such as immunoassay, GC-MS, LC-MS/MS),

• Cut-off values ​​(the threshold value that the laboratory considers positive).

Therefore, detection times cannot be determined with precise lines; they are always evaluated based on "average" times.

---

Detection Times by Drug Type

1. Cannabis (THC)

• In the blood: 2–12 hours (several days with heavy use).

• In urine:

  • 1-3 days for single use,

  • With regular use, 7-10 days,

  • Up to 30 days (45 days in some cases) for chronic addicts.

• For hair samples: up to 90 days.

• In saliva: 24–72 hours.

📌 In Supreme Court rulings, the fact that cannabis metabolites can remain in urine for a long time has been taken into consideration and accepted as sufficient evidence for the "crime of drug use".

---

2. Cocaine

• In blood: 6–12 hours, its metabolite benzoylecgonine ≈ 48 hours.

• In urine: 2–4 days, 7–14 days with intensive use.

• For hair: 90 days or more.

Cocaine is rapidly metabolized, which is why it shows up in blood tests only after a short time. However, its metabolites remain in urine for a longer period.

---

3. Amphetamine and Methamphetamine

• In the blood: 12–24 hours.

• In urine: 2–3 days, 5–7 days with heavy use.

• In hair samples: It can be detected for months.

📌 The 20th Criminal Chamber of the Supreme Court of Appeals, in its decision numbered 2019/3562 E., 2020/1274 K., accepted the detection of methamphetamine in the defendant's urine as sufficient evidence for the "crime of drug use" under Article 191 of the Turkish Penal Code.

---

4. Heroin (Morphine derivatives)

• In the blood: 6–12 hours.

• In urine: 1–3 days, in some cases 5–7 days.

• In the case of hair: For months.

Heroin is rapidly metabolized and quickly converted into morphine. Therefore, its detection time is shorter compared to cannabis.

---

5. MDMA (Ecstasy)

• In the blood: 12–24 hours.

• In urine: 2–4 days.

• On hair: 90 days.

---

Legal Assessment

1. Nature of the Evidence

Drug tests can prove that a person has used drugs. However, when they used them or whether they were under the influence of drugs on the date of the incident . Therefore, the defense of "past use" is frequently put forward.

2. Supreme Court Case Law

• The 10th Criminal Chamber of the Supreme Court of Appeals, Case No. 2017/2719 E., Decision No. 2018/3456 K.
  , found cannabis metabolites in the defendant's blood and accepted that this was sufficient for the "crime of drug use".

• The 20th Criminal Chamber of the Supreme Court of Appeals, Case No. 2019/4512 E., Decision No. 2020/3274 K.,
  found amphetamines in the defendant's urine. The Court emphasized that this indicates past use, but whether the defendant was under the influence of drugs at the time of the incident should be further investigated.

3. Use in Defense

• The validity of the test is questionable (chain protection, laboratory procedures).

• Its prolonged presence in urine supports the argument that it may be ineffective at the time of the incident.

• AMATEM reports contribute to the assessment by revealing whether a person is addicted or not.

---

Concrete Event Narratives

Case 1 – Favorable Situation

Defendant A. was stopped at a traffic checkpoint. A urine test came back positive for cannabis metabolites. However, the defendant stated that he had used it 20 days prior. The AMATEM (Addiction Treatment Center) report also indicated that THC can remain in urine for up to 30 days. The court concluded that A. was not under the influence of drugs on the date of the incident.

Case 2 – Unfavorable Situation

Defendant B. was apprehended with methamphetamine in his possession. A blood test taken the same day revealed the presence of active methamphetamine. This showed that he not only possessed it but had also used it recently. The court sentenced him under Article 191 of the Turkish Penal Code.

---

Conclusion

The time it takes for a drug to be detected in blood and urine varies depending on the substance used, the frequency of use, the individual's metabolism, and the testing methods. In general:

• Blood tests take a short time (hours – 1 day),

• Urine tests, on the other hand, provide detection over a longer period (days – weeks)
  

Legally, this data constitutes evidence in proving drug use, but it is not sufficient on its own to show whether the person was under the influence of drugs at the time of the incident. Therefore, the time frame for detection, AMATEM (Addiction Treatment Center) reports , and the method of obtaining the evidence must be taken into account in defense strategies.

---

📌 Note: These times are “average” values. Individual metabolic rate, amount used, frequency of use, and laboratory test methods may alter the results.

Allegations of Passive Smoking in Drug Tests and Supreme Court Decisions

Entrance

In drug use offenses (Turkish Penal Code Article 191), one of the most important pieces of evidence is blood and urine tests. However, in some cases, the suspect or defendant may claim that the drug entered their body not voluntarily, but passive smoking .

The claim of "passive smoking" is frequently raised, particularly in cannabis (THC) cases. This is because exposure to cannabis smoke in an enclosed space can detect low levels of metabolites. However, this claim is not always legally accepted and is evaluated according to the specific circumstances of the case.

---

The Medical Aspects of Passive Smoking

According to scientific research:

• Individuals exposed to heavy cannabis smoke in enclosed, poorly ventilated environments may have THC metabolites detectable in their urine for a short period

• However, this amount generally at low levels .

• The difference between regular users and passive smokers can be distinguished by the higher levels of metabolites detected in tests.

📌 Therefore, for the passive smoking defense to be accepted:

• The amount used is very low,

• Lack of evidence regarding the defendant's intent to use the property,

• The test results should show low levels of metabolites .

---

Supreme Court Decisions

📌 The 10th Criminal Chamber of the Supreme Court of Appeals, Case No. 2015/8764 E., Decision No. 2017/4356 K.
A low amount of THC metabolite was found in the defendant's urine. The defendant argued that he was in a social setting with friends and did not smoke cannabis himself. The Supreme Court of Appeals stated that due to the low metabolite level and the lack of other evidence, the possibility of passive smoking could not be disregarded .

📌 Supreme Court of Appeals, 20th Criminal Chamber, Case No. 2019/2456 E., Decision No. 2020/3472 K.
Cannabis residue was found during a search of the defendant's home, and high levels of metabolites were detected in his urine. The defendant's defense of being a "passive smoker" was rejected due to the high metabolite levels.

📌 The Supreme Court Criminal General Assembly, in its decision numbered 2016/10-874 E., 2018/246 K.,
that the claim of passive smoking cannot be accepted on its own and a detailed analysis of the specific circumstances of the case and the test results .

---

Concrete Event Narratives

Case 1 – Favorable Situation

Defendant A. was sitting in a cafe with a group of friends while the others were smoking marijuana. During a police raid, a sample was taken from the defendant. A urine test revealed low levels of THC. Due to the lack of other evidence and the low metabolite levels, the court accepted the defense of passive smoking.

Case 2 – Unfavorable Situation

Defendant B. was apprehended at his home. Packages of marijuana were found in the house. High levels of THC metabolites were detected in his urine. The defendant claimed to be a passive smoker. However, the Court of Cassation rejected this defense due to the overwhelming amount of evidence.

Event 3 – The Controversial Situation

Defendant C. was found among a crowd smoking marijuana at the concert venue. A test conducted the following day revealed the presence of THC in his urine. No drugs were found on the defendant or in his belongings, and metabolite levels were low. In this situation, the possibility of passive smoking can be strongly emphasized in the defense.

---

Defense Strategy

• Laboratory reports should be examined in detail, and if metabolite levels are low, the defense of passive smoking should be considered.

• This defense is stronger if no drugs are found on the defendant, in their home, or in their vehicle

• An AMATEM (Addiction Treatment Center) report should be requested to prove that the person is not an addict.

• Scientific articles demonstrating the possibility of passive exposure in enclosed and crowded environments can be presented as evidence.

---

Conclusion

The claim of passive smoking can be an important defense tool in drug use offenses, especially in cannabis cases . However, in the practice of the Supreme Court of Appeals:

• metabolite levels are low and there is no other evidence, the likelihood of acceptance is high.

• if the metabolite level is high or if drugs are found on the sample.

From a defense perspective, it is critical that this claim be supported by scientific reports and the circumstances of the event

                                                                                                                                 Law Faculty Student Ada Ceren KENDİGELEN