Purchase your DNA test and any additional test options here.
If you are purchasing a DNA test for immigration purposes or a purchasing a forensic test, please contact us first.

If you have any questions, or if you'd like to discuss your personal case, please contact us on 02 381 5410, 086 347 7620, or thailand@ptclabs.com.

Twin Zygosity Test

Twin Zygosity Test

Price: THB 15,900



Twin Zygosity Testing identifies whether twins are identical or fraternal twins. This type of testing would usually be done shortly after birth to satisfy the curiosity of the parents. You would also perform this test to aid in a medical emergency, such as an organ or blood donation. 

  • Fraternal (Dizygotic) twins are conceived from separate eggs and sperm; usually two (2) eggs and two (2) sperm. These type of twins will have 2 distinct DNA profiles. 
  • Identical (Monozygotic) twins are conceived from one (1) egg and one (1) sperm that split into two (2) embryos. This results in the twins having identical DNA. 

A simple mouth swab is all that is needed to get a DNA sample from each of the tested parties, however, some unusual samples are accepted. Note that most unusual samples will incur a fee, as we must first extract the DNA in order to analyze it. Contact us for more information. 

Before purchasing this test, it is important to contact us first, to discuss your requirements and whether this is the right test for you.

Whether you need a Peace-of-Mind (At-Home) Test, or a Legal (Chain-of-Custody) Test, the actual lab testing and analysis is identical, with the same level of rigorous testing methods. The only difference for a legal test is in how your samples are collected (see below).

The price for this test includes:

  • 24/7 personal customer support in English and Thai.
  • DNA Sample Collection Kit, containing everything you or your sample collector need to collect samples and complete paperwork. Note that this test fee does not include the Chain-of-Custody (CoC) Fee for legal sample collection, which is paid directly to your sample collector. Please see below for extra information regarding Legal Tests and the additional Chain-of-Custody (CoC) Fee.
  • One (1) shipment of your samples (up to 0.5 kg in one shipment) by first-class, international priority courier to our lab in the USA.
  • Testing of DNA samples provided on cotton tip for for two (2) people who are twins. To test additional people, you will need to add this option to your order. Scroll down the page to add this option to your order. To use unusual samples in this test, you will need to add this option to your order. Scroll down the page to add this option to your order. 
  • One (1) original, notarized English-language report, and one (1) original, notarized Thai-language report.
  • Emailed results as soon as they are ready.
  • Posting of hard-copy, notarized results to anywhere in the world by regular mail. To express the postage of your hard-copy results, you can upgrade to first-class, international priority courier. Scroll down the page to add this option to your order.


Tests required for legal or official purposes must follow a strict chain-of-custody of the samples, and will incur an additional Chain-of-Custody fee, which is payable directly to your sample collector. This fee covers the collection of DNA samples by a certified, independent third party, the chain-of-custody of samples, and the identification verification process. Learn more about chain-of-custody of samples in our FAQ.

Following this process means your notarized result report will also be recognized as an official, legal document (note that foreign-issued legal documents used in Thailand also need to be authenticated after they are issued. Learn more about the difference between notarized, legal, and authenticated results in our FAQ.) 

The sample collector could be your own doctor (with pre-clearance from PTC), one of our world-wide, certified collection centers, or a PTC representative from our Bangkok office.

  • If you will visit our Bangkok office for your sample collection, or if one of our Bangkok PTC representatives will visit you at your home, hotel, or hospital, you can add the payment for Legal Sample Collection by PTC option to your order. Scroll down the page to add this option to your order.
  • For all other sample collections, you must pay your sample collector directly. Contact us if you need more information or need to find a certified sample collector near you.

Important Information


  • A Twin Zygosity Test can be used for your own peace-of-mind (you collect your own samples), or for legal, official purposes (your samples must follow a strict strict chain-of-custody procedure, meaning the DNA is collected by a certified, independent third party, and your identity has been verified and documented). Learn more about the difference between legal testing and peace-of-mind testing in our FAQ. 
  • The results could be used to satisfy the curiosity of the parents, or to aid in a medical emergency, such as an organ or blood donation. 
  • If you plan to use your results for any legal or official purpose in Thailand or Taiwan, there is an Authentication Process that must be followed, and we can take case of the whole process both in the USA and in Thailand. Scroll down the page to add this option to your order.
  • Our results are accepted in many countries around the world for Immigration and other official purposes. If you are using your results for Immigration purposes, please read our section on Immigration Testing, and contact us for more information about your specific Embassy, as some Embassies require you to first make an application with them, before doing a DNA Test.


  • Testing times can vary depending on the samples provided. Generally, for tests with good oral samples, it will take a total of approx. 7-10 business days. Tests using unusual samples will take longer. This includes both the time it takes to send your samples to our lab in the USA (2 business days) by first-class, international priority courier, and also the testing time at our lab. 
  • We provide a guarantee based on our 99.99% probability of the relationship. This means that we will continue testing until we reach this probability, at no extra cost to you. This can also mean that our usual 1-2 week window of testing can take longer if, for example, the Mother's sample is not included in the test, there are mutations in the DNA from one tested generation to the next, the samples contain a high bacteria count, or other reasons that are out of our control. 
  • This is why we do not guarantee how long it will take to deliver results, but we guarantee the accuracy of our results.
  • If you are in a hurry, we have an express testing option. Note that if we cannot get a minimum of 99.99% probability within the express timeframe, you will be refunded for the express fee. Scroll down the page to add this option to your order.
  • Your results will be sent to you immediately by email. Your physical results will be sent to your via regular post and will arrive in Thailand approximately 2 weeks after you receive your emailed results. 
  • If you’re in a hurry, you can also opt to have your results sent via first-class, international priority courier for an additional fee, and your results will arrive within approximately 2 business days. Scroll down the page to add this option to your order.


The report you will receive will show at least 99.99% probability of the twins being fraternal (Dizygotic) twins, or at least 99.99% probability of the twins being identical (monozygotic) twins. This guaranteed probability is above industry standards, and we will not issue a result that does not match this conclusive level of probability.  


  • Samples are usually collected using buccal swabs (sterile Q-Tip/cotton tip) - which are provided in our DNA Sample Collection Kits - by swabbing the inside of the cheek. If you are collecting your own samples for a Peace-of-Mind (PoM) Test, you can view our sample collection guidelines here.
  • If normal samples are not possible to obtain, you can view our Unusual Samples page to see what other types of samples can be used for this test. Most unusual samples will incur a fee, as we must first extract the DNA in order to analyze it. Contact us for more information.


Legal Sample Collection by PTC

THB 1,500

Visit Service (<15 km)

THB 500

Express Testing

THB 4,800

Visit Service (15-35 km)

THB 1,000

Express Authentication (per Case)

THB 6,600

Express Delivery (Courier)

THB 2,700

Visit Service (35-100 km)

THB 2,000

Unusual Sample (per Sample)

THB 8,300

Additional Person

THB 7,500

Visit Service (100-200 km)

THB 3,000