Quick Facts
Test Type	Twin Zygosity Test, Twin Test
Individuals Involved	Twins
Description	To determine the zygosity of twins, or determine whether twins are identical or fraternal.
Fee for Private Home Test [?]	$180 US for testing twins
Fee for Court-Admissible Home Test [?]	$255 US for testing twins
Fee for Legal Test [?]	$355 US for testing twins, plus specimen collection fee
Specimen	Buccal swab (blood is also acceptable but not recommended)
Turnaround Time	Regular: 3 to 5 business days, Express: 2 - 3 business days
Method of Reporting	Mail, Email, or Telephone
Ordering	This test can be ordered by phone, fax, mail, or online:  By phone: 1-888-262-2263  By Fax or mail: download a printable private test order form  Order online: order online 24 hours a day

A question which is commonly encountered by families with twins is "are they identical or fraternal?" The twin zygosity test is used to conclusively determine whether twins are identical or fraternal.

Knowing whether twins are identical or fraternal is often difficult. Appearance alone often is not a reliable method in determining twin type because identical twins do not always look exactly the same, and fraternal twins can sometimes look very similar, leading to confusion about exactly what type of twins they are. Sometimes, twins grow up never knowing for sure whether they are identical twins or not.

At the time of birth, the physician will try to get an idea of whether twins are identical or fraternal by examining whether they share the same sac. Identical twins often form in a single sac, sharing a placenta and amniotic membranes. Fraternal twins often form in two separate sacs. However, up to 25% of the time, this method of determining twin type is not accurate and can be very misleading. In some cases, twins can have two sets of outer sacs (dichorionic) and still be identical twins. Also, the two placentas of fraternal twins can sometimes fuse together and appear to be one.

The only way to conclusively determine whether twins of the same sex are identical is through a simple DNA test. For this reason, many parents of twins will consider a private DNA test for twins to determine conclusively whether the twins are identical or fraternal. The DNA twin test is fast, simple and painless. A DNA sample is taken from each child by rubbing a painless swab gently inside the child's mouth for ten seconds. The samples are then submitted to the laboratory for testing and conclusive results are available within 5 days.

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Applications of Twin Test

	Parents of twins who need to find out for sure or to confirm their suspicion.
	Twins who want to know whether they are definitely identical twins or whether they are fraternal.
	This test is also applicable for other types of multiples (e.g. triplets, quadruplets, etc.)

Step-by-Step

Step 1 - Order the test. Order laboratory testing by phone at 1-888-262-2263 or by mail, or click here to order the private DNA collection kit online.

Step 2 - Collect and submit the samples to the laboratory. Kits are delivered to your door within 24 hours by courier or within 5 working days by mail. Each Twin test kit comes complete with all of the collection materials and instructions for you to take the test in the privacy of your own home. All Twin testing kits employ the buccal swab technique, allowing you to perform the collection within minutes with no fuss, no pain. Submit the DNA specimen directly to the laboratory after collection.