Oocyte Choromosome Status Test-Home

Oocyte Chromosome Status (OCS) test is an innovative procedure to confirm the competency of embryo by identifying the presence of all 23 of chromosomes.


	Oocyte Chromosome Status (OCS) test is an innovative procedure to confirm the competency of embryo by identifying the presence of all 23 of chromosomes. Most competent embryos result in successful pregnancy, but almost all chromosomally abnormal (aneuploidy) embryos are eliminated before implantation. It is speculated that the major cause of In-Vitro Fertilization Embryo Transfer (IVFET) procedure failure is aneuploid embryos. Most of the aneuploidy occurs at a pre-zygotic stage: since sperm yields less than 1% of aneuploidy, it can be inferred that the aneuploidy observed arises mainly from the oocyte. Please Note: The aneuploidy observed in conceptus and newborns probably originated from the oocyte. Selection of oocyte with full complement of chromosome may therefore promote the IVFET success. OCS is such a test utilizing state-of-the-art nested multiplex PCR technology on polar body to identify oocytes with full complement of chromosomes (22 autosomes and X chromosome).

What is OCS Test!

Oocyte Chromosome Status test is a method of confirming the presence of all of the chromosomes present in the oocyte (egg) before implantation of the embryo.

Each cell contains 22 pairs of autosomes and one pair of sex chromosomes. During maternal gametogenesis (meiosis), the numbers of chromosomes are halved. One half of the chromosomes are retained by the oocyte while the remaining half is discarded with the polar body (PB). For more details: chromosomal abnormalities

Please Note: PBs are by-products of meiosis and therefore can be analyzed to detect aneuploidy of the oocyte without injuring it.

The first polar body is produced after the first meiosis at the time of oocyte retrieval.
The second polar body is produced upon sperm penetration into the oocyte, but prior to joining of the sperm’s genetic material with that of the oocytes genetic material.

Rationale:
In normal meiosis I, The PB1 contains one copy of all maternal chromosomes, while non-disjunction results in zero or two copies in about 70% of aneuploidy oocyte. In normal meiosis II, PB2 contains a full set of maternal chromatids; non-disjunction results in zero or two copies in about 30% of aneuploidy oocyte. Unlike the oocyte, sperm yield less than 1% of aneuploidy.

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Oocyte Chromosome Status test is a method of confirming the presence of all of the chromosomes present in the oocyte (egg) before implantation of the embryo.