How long should cigarette butts be kept before paternity test can be done?

I believe many people will see the police taking cigarette butts for paternity test on TV. In fact, cigarette butts can be used for paternity testing, and the accuracy will be high. So, how long should I keep cigarette butts for paternity testing? How to do blood type paternity test? Let's take these two questions to see the correct answer.

How long should cigarette butts be kept for paternity test? 1. It is recommended not to exceed 15 days.

2. But cigarette butts are special samples and can be used for personal identification. Collection method: after smoking, wrap the cigarette holder with paper towel, cut off the cut tobacco and leave only the cigarette end, wrap it with paper towel and put it in an envelope for preservation. It is best to mail or express it to the appraisal center within 2 weeks.

Paternity identification of cigarette butts is risky, because cigarette butts themselves are a medium, and the final identification is human tissues. If the amount of human tissue attached to cigarette butts is extremely small, there is a risk of identification failure, so cigarette butts are difficult samples in paternity testing.

Matters needing attention in identification with cigarette butts:

1. cigarette butts are easy to be polluted by the environment, and it is not necessarily guaranteed that genetic information can be extracted, so it is best to collect more in the collection process, and generally genetic information can be extracted.

2. cigarette filter should not have a smooth surface.

Pay attention to washing hands when picking up cigarette butts. Don't touch cigarette butts directly. Try to put clean tweezers or toilet paper in a clean envelope and mark it.

4. After the sample is collected, send it to the identification center as soon as possible.

Samples needed for paternity test

Personal paternity test: you need to provide samples, blood samples, 5-6 hairs with hair follicles, or wipe the inner wall of the mouth, nails, toothbrush, etc. for 5-6 times. Use a cotton swab.

Paternity test during pregnancy: pregnant women need to take 10ml venous blood after more than 5 weeks of pregnancy, and men can take 3ml venous blood or provide other samples (nails, hair, pure semen spots, etc.). ) do a paternity test.

How to do blood type paternity test mainly depends on the type of blood test, and you can get the required sample by pricking your finger. Blood is the most preferred sample, which is simple and quick, and can also be anticoagulated with 1 ml.

There are four main steps in blood type paternity test:

1. Extract cells from blood, destroy the cell membrane and nuclear membrane by physical or chemical methods, and release the DNA in the nucleus.

2. Using this kit, a small amount of DNA can be converted into the amount needed for PCR detection.

3. Put the sample into the gene sequencer, and get the analysis result through electrophoresis detection.

4. Testers evaluate and calculate the test results, and draw a final conclusion.

The blood group systems used for blood group test and paternity test mainly include ABO blood group system, MN blood group system, Rh blood group system, Ss blood group system and hp blood group system. The more blood group systems tested, the higher the accuracy. If the blood type test results show that there is no kinship, it can be concluded that the parent-child relationship is negative, but the result of kinship cannot be completely determined.