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Ask Dr. D. Love Your Own Question
Dr. D. Love
Dr. D. Love, Doctor
Category: Drug Testing
Satisfied Customers: 17548
Experience:  Family Physician for 10 years; Hospital Medical Director for 10 years.
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My questions are regarding cocaine detection on hair drug test.

Customer Question

My questions are regarding cocaine detection on hair drug test.
If you consumer cocaine during several hours throughout one night, is that consider a single use?
How do the odds of passing a hair drug test increase at 62 days and 82 days?
Is it possible that at 90 days since consumption, the hair drug test could still detect the cocaine because it takes 7 to 10 days for cocaine to get into your body?
Submitted: 1 year ago.
Category: Drug Testing
Expert:  Dr. D. Love replied 1 year ago.
Hello from JustAnswer.
A hair follicle drug test is not good at detecting drug use on a single day, even if there was use over several hours on that day. However, if there is a chance that it would detect drug use on a single day, it is someone that used a large amount of drugs on that day that would be detected. It is more the total quantity of drug that was used on that day that is the important variable, not the number of hours over which it was taken.
Within that context, it does not matter which day of the 90 days was involved in the drug use. The likelihood of detection would be the same if it were on day 62 as on day 82.
It is possible that the drug could be detected at 90 days. You are correct that it takes at least 5-7 days for the drug to be detected in the hair. This has more to do with the process of hair growth. The drug is incorporated into the hair as the drug is in the blood stream, but it then takes a while for that growing portion of hair to extend sufficiently up to the hair to be detected on the drug test. The drug test is a 90 day test, but that is an approximation based on average hair growth. However, since there is at least a 5-7 days lag before it can be detected, the hair drug test could potentially detect drug use up to 95-100 days.
If I can provide any further information, please let me know.
Customer: replied 1 year ago.
hi Doctor,
Thank you for your response. I understand that's more important the quantity than the time. The quantity was somewhere between 1 and 1 and a half grams of cocaine. Is that considered a high quantity?I assume that at 82 days you potentially have a bigger chance of not being detectable than at 62, because you are getting closer to the 90 days date. So I assume as time pass the amount is diminish, isn't it? Is that right?
Expert:  Dr. D. Love replied 1 year ago.
This is a common dose of cocaine, but there is no good data of the amount that would be considered a threshold.
No, the amount is not diminished with time. The drug is incorporated into the hair at the base as it grows, and then the segment of hair that contains drug will gradually grow out from the scalp over time. But since the drug is incorporated into the inside of the hair, the level does not diminish, only the distance from the scalp. The test is a 90 days test because the length is cut to the length that would be expected based on the average growth rate of hair. Since hair grows an average of 1/2 inch per month, the hair length is cut to 1 1/2 inches, which would correspond to 90 days of hair growth. If you could imagine dividing that 1 1/2 inches into 90 equal segments, then each segment would represent a day. If the test is done 62 days after the drug use, then it would be the 62nd segment that would contain the most drug (there would be some metabolites present on subsequent days). If the test is done 82 days after use, the 82nd segment would contain the most drug. But if you were to be able to compare the two segments from the two different days, those particular segments would be similar and not diminished.
That is why I said above that it does not matter which day of the 90 days was involved in the drug use. The likelihood of detection would be the same if it were on day 62 as on day 82.
Customer: replied 1 year ago.
Thank you Doctor. So I have done a private test in the same lab that I have to do the work test. Based on your insight, if I am positive on this test that's done 62 days after consumption, I should see the same results at 82 days? But then at 90 days I could be free from it already?What about hair growth rate? How flexible is the 90 day mark?
Expert:  Dr. D. Love replied 1 year ago.
Yes, the 82 day test would be similar to the 62 day test. However, the test does not automatically end at 90 days, cause the test does not really start until at least 5-7 days after the use of the drugs, as we discussed above.
In addition, as I noted above, that is an approximation based on average hair growth, but the hair growth rate can vary by 10-20% commonly. So, even the 90 days from when the drug can be first detected is only an average and cannot be taken as a strict cut-off.
Customer: replied 1 year ago.
Thank you Doctor.
My hair grows fast so I'm hopeful the process is faster on my side than the standard 90 days. Assuming it grows 10% faster than average would 82 days be safer?Given all the information above what's your estimation of the odds based on your experience?Thanks,
Expert:  Dr. D. Love replied 1 year ago.
If you are certain that your hair grows faster, then 82 days would be safer. Most people, though, cannot be certain of their hair growth, so it is usually better to assume a slower hair growth, in which case 110-120 days would be a safer period.
Customer: replied 1 year ago.
Thank you for all the timely answers but I haven't got an answer on whether based on your expertise the quantity I took was significant or not to show in the test. Also what are the chances of the test being positive.
Expert:  Dr. D. Love replied 1 year ago.
As I said above, this is a common dose of cocaine, but there is no good data of the amount that would be considered a threshold. Similarly, there is no study that has said what the odds are of a positive result based on the dose on a single day.
Customer: replied 1 year ago.
Not very helpful but I understand
Expert:  Dr. D. Love replied 1 year ago.
If a study has not been done, then it has not been done.
Customer: replied 1 year ago.
I understand there's no studies on it. I would like the experts judgement based on experience. Not the scientific study quantitative results. Thanks
Expert:  Dr. D. Love replied 1 year ago.
I have never had a patient get a positive result and claim that the drug was used but only on a single day, but that is a misconception, because that assumes that every patient that has a positive or negative test will honestly admit how they used an illegal substance, including reliably reporting that it was used only on a single day. Since we cannot assume that patients will be honest about illegal drug use, a doctor’s personal experience typically is not reliable.
Customer: replied 1 year ago.
Thank you Doctor. Good answer.Could using Biotin 10,000 for my hair during a couple of weeks help at all?
Expert:  Dr. D. Love replied 1 year ago.
There is no evidence that taking biotin will increase the likelihood of passing a hair follicle drug test.
Customer: replied 1 year ago.
Also another question. If my test results at 62 days are negative, would that mean that if I test my hair anytime after that day in the same facility and without having consumed anything else, I will always get the same results. Or results can vary?
Customer: replied 1 year ago.
Is there evidence that Biotin makes your hair grow faster?
Expert:  Dr. D. Love replied 1 year ago.
Yes, if your test at 62 days is negative in the same lab at which it will ultimately be tested, then it will be negative any time after that date in the same lab, assuming that there is no further drug use.
Since different labs may use different methodologies and thresholds, it is not predictive between labs, but you stated that you are getting tested in the same lab, which would be predictive.
There is some use of biotin to help with hair growth in someone with hair loss or other disturbances in hair growth, but three is no evidence that it will cause healthy hair to grow faster.
Customer: replied 1 year ago.
Thank you Doctor! I appreciate the answers.
Expert:  Dr. D. Love replied 1 year ago.
You are most welcome.
If I have answered all your questions, please remember to provide a positive rating so that I am credited for assisting you.
Customer: replied 1 year ago.
Thank you Doctor. I will do so.
One further question: is Cocaine easier to identify as a single use drug on hair testing to other drugs such as THC?Also, I dye my hair frequently for aesthetic reasons, does that affect favorable even a little bit the chances to get a negative test result.
Expert:  Dr. D. Love replied 1 year ago.
Cocaine is considered easier to detect, but that is more because THC is more difficult to detect on hair testing.
It depends upon the hair dye. Some hair products, including hair dyes, use strong bleaching agents, and the stronger products can damage the hair and allow loss of the drug from the inside of the hair. In some studies, this can result in loss of about half of the drug in the hair, so it is more than just a small effect. Consequently, it would increase the likelihood of passing a hair drug test for someone that is closer to the threshold of detection. In someone that uses drugs more frequently, such as daily use, they will still likely fail the test, but in someone with infrequent use, the chances of passing the test would increase.
Customer: replied 1 year ago.
Hi Doctor,Thank you for all your good anawers. I have one more question please. How does the test work? If they don't let you know the results in 48h, does that mean that you are positive and they are validating the quantity? Could you still be negative? Or they only validate the second phase when you are above the minimum?Thank you!
Expert:  Dr. D. Love replied 1 year ago.
The procedure can vary from one lab to another. But the general procedure is to first perform a screening test by immunoassay to see if anything is positive and then only do the confirmatory test if one of the screening test is positive.
The screening test will typically be done within 48 hours once the specimen is in the lab. Whether the screening test can be completed within 48 hours of collection would depend partly on the physical proximity of the lab to the collection site. There may need to be transportation time incorporated into the turn around time. Many of the national labs will have collection sites in many cities, but still send certain labs to a centralized location, so there may still need to be transportation time.
Any lab also would need to deal with workload issues, including illness or vacation of workers or a large number of labs to process, so a delay of 48 hours within the lab could reflect workload issues rather than a positive screen.
Therefore, taking longer than 48 hours can be due to many factors other than a positive screening test, so it also is true that you could still be negative.
Customer: replied 1 year ago.
Doctor,
I've read in some places that cocaine is highly detectable in hair drug tests even for single use. On other sites they claim that it is only valid for frequent consumption. What's the science on all this? Is hair test developed for continuos or single use detection?
Expert:  Dr. D. Love replied 1 year ago.
As I said above, there are no studies that identify a threshold of consumption at which the test may turn positive. From a medical perspective, it does not matter to us whether it is one use or 90 uses over the 90 day period. From a medical perspective, the issue of single use versus continuous use is irrelevant. This is an issue that is only important to the people hoping to pass the test.
The only real concern from a medical perspective is that it will accurately identify the most people that have used drugs without falsely identifying innocent people, such as someone that has been in the same room as a person using drugs.
So, the studies that address the issue of single versus continuous use or a threshold at which the test will detect the user do not exist.
I realize that you would like a study to reassure you of this issue, but as I said before, if the study does not exist, then the study does not exist.

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