FAQs for Chuangxing Model RDTD19H On-site Trace Hair Drug Detector 1 Test Samples 1.1 Q: How soon can drug use be detected via hair testing? A: Based on the average hair growth rate, drug use can be detected 15 days after ingestion. It is imperative to cut new hair strands close to the scalp for testing. Depending on hair growth, drug use within the longest 3–6 months can be detected (for individuals with longer hair, the window can even extend to 6–12 months). In contrast to the 1–3 day detection window of saliva and urine tests, hair testing clearly provides insights into drug use over a much longer period.
1.2 Q: How to collect and preserve hair samples? A: For hair collection, cut 10–15 hair strands of 10 cm in length close to the scalp at the back of the subject’s head (this area receives the best nutritional supply from the body and is the optimal region for testing). Place the collected hair flat in a clean paper bag or sealable plastic bag, and store it at room temperature under normal conditions.
1.3 Q: Can bleached and dyed hair be used as test samples? Will it affect test results? A: Yes, it can. Bleaching and dyeing have little to no impact on test results in most cases, because most hair dyes used for bleaching are mineral-based and have different molecular formulas from drugs, thus causing no interference. However, there are special cases: for example, ash gray hair – repeated bleaching and perming often alter most of the hair’s physical properties, which may cause a certain degree of interference to test results. This reminds us to pay extra attention to suspects with ash gray hair and collect their body hair or hair roots for testing whenever possible.
1.4 Q: Can drug content be detected in the hair tips of women with long hair? A: For women who abuse drugs frequently over a long period, their hair tips can be used as test samples. For hair longer than 10 cm, sectional testing is recommended: cut the hair close to the scalp, take half of the hair root segment for one test, and then take half of the hair tip segment for another test.
1.5 Q: What to do if a suspect is bald? A: Body hair such as chest hair, pubic hair, facial hair or leg hair can be collected as an alternative test sample.
2 Test Procedures 2.1 Q: What is the purpose of the ID card in the kit? Can it be shared across different reagents? A: The ID card is used for identity recognition of the test strip and instrument calibration. It cannot be shared across different reagents or different batch numbers.
2.2 Q: How to properly cut hair during the testing process? A: Take 5 mg of the hair to be tested (approximately 10 strands of 10 cm in length), and cut it into 1–2 mm segments on a folded weighing paper. To meet the needs of grassroots law enforcement work, we have specially equipped the detector with a high-precision electronic balance (with an accuracy of 1 mg, i.e., 0.001 g), which enables precise weighing of hair for quantitative testing and minimizes the impact on experimental results.
2.3 Q: Can hair be tested directly without lysis buffer? A: No. The cut hair segments must be poured into a bottle containing Lysis Buffer A , the cap tightly sealed, and the bottle shaken and mixed on the sample preprocessor for 1 minute. Then add Buffer B for sufficient reaction, shake and mix on the sample preprocessor for another 15 seconds. Finally, use a dropper to extract the upper middle layer of the lysed hair solution and add 3–4 drops to the sample well of the test strip.
2.4 Q: Are hair lysis buffers universal across different tests? A: Yes. Lysis buffers for different test items all contain proteases (the essential function of a lysis buffer is to hydrolyze proteins in hair), so they are universal.
2.5 Q: Are there any requirements for hair lysis time? What are the impacts of insufficient or excessive lysis time? A: The hair lysis process must last for 1 minute. Insufficient lysis time will lead to incomplete hydrolysis and thus affect test results. Excessive lysis time will prolong the entire testing process and reduce detection efficiency, so it is not recommended.
2.6 Q: How long after sample application on the test strip can it be loaded into the detector for testing? A: After sample application, the test strip must be incubated on a thermostatic incubator at 37°C for 5 minutes (this is our proprietary technology – constant temperature incubation minimizes the impact of temperature and environmental factors on test results). Immediately insert the test strip into the detector after incubation, and click the "Test" button. The system will automatically read the strip and display results within 3 seconds. Results read after more than 10 minutes are unreliable and deemed invalid.
2.7 Q: The detector displays test options for skin, powder, paper and other samples – can these be used? A: Their use is not recommended for the time being. Testing should be focused on hair samples. These functions can only be used after our company develops and matches corresponding new test kits in the future.
2.8 Q: What if lysis buffer cannot be refrigerated when the detector is used in the field? A: Lysis buffer can withstand short-term non-refrigerated storage and can be transported and used at room temperature. Unused lysis buffer must be refrigerated immediately after being brought back to the lab/station.
2.9 Q: How many samples can one detector test at the same time? A: One detector can test one sample at a time , and test strips can be replaced repeatedly and quickly.
2.10 Q: Does the detector come with a warranty? Are the subsequent maintenance costs high? A: Free software upgrades ; two-year warranty for hardware ; lifetime maintenance is provided, and the maintenance cost is priced based on the spare parts to be replaced.
3 Result Interpretation 3.1 Q: Can test results be obtained with test reagents not produced by your company? A: No. The test strips and their components are only compatible with the trace hair drug detector manufactured by our company.
3.2 Q: How can I verify the accuracy of the detector’s test results? A: The detector is equipped with a built-in quality control line detection system . Abnormal tests will trigger an alert and no results will be displayed. Valid results indicate a normal testing process and are reliable.
3.3 Q: What is the valid time window for reading test strip results? What are the impacts of reading too early or too late? A: The valid reading window is 5 to 10 minutes after incubation. Results read before 5 minutes of incubation or after 10 minutes (due to oxidation) are unreliable.
3.4 Q: What do the numerical values in the test results represent? How to interpret them? A: The numerical value indicates the drug content per milligram of the tested hair sample .
Result Determination Supplement Based on the latest laboratory test results and joint definition discussions with multiple industry peers, a hair drug test result above 0.2 ng/mg can be determined as positive. However, the current national standard still adheres to the previous benchmark of 5 ng/mg . Thus, we can classify results ranging from 0.2 to 5 ng/mg as weak positive . In such cases, it is recommended to implement control measures for the suspect, but not necessary to submit the sample to a professional laboratory for further testing —as most laboratories still follow the traditional 5 ng/mg benchmark for result determination. If a suspect’s test result exceeds 5 ng/mg, the suspect can be officially identified as a drug user, and the sample may be submitted to a laboratory for professional authentication to serve as formal law enforcement evidence.
4 Storage 4.1 Q: How to store the detector and matching test kits before testing? A: Store the detector in its instrument case at room temperature, with the case placed on a level surface .
Store the matching test kits in accordance with the markings on the packaging surface and the recommended storage conditions specified in the instruction manual.
Test strip storage conditions : 4–30°C, in a cool and dry place; freezing prohibited .
Hair lysis buffer storage conditions : Keep in the original lysis buffer packaging bag and store at 2–8°C.
4.2 Q: How to store unused test kits? A: Store them in accordance with the markings on the kit packaging surface and the recommended storage conditions in the instruction manual.
Test strip storage conditions : 4–30°C, in a cool and dry place; freezing prohibited .
Hair lysis buffer storage conditions : Keep in the original lysis buffer packaging bag and store under refrigeration at 2–8°C .
4.3 Q: Can the test products be used if the expiration date on the test kit has passed at the time of use? A: No, expired reagents must not be used. Expired reagents will only interfere with test results, which defeats the fundamental purpose of accurate testing.
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