Collaborative Stage

Note 1: This is a special molecular diagnostic test performed on tumor tissue to identify loss of genetic material normally found on the long arm of one of the patient's two copies of chromosome 18. A normal cell will contain two complete copies of each chromosome, one from each parent, and this normal state is termed heterozygous. Loss of heterozygosity (LOH) is an abnormal state reflecting damage to the chromosome that may mean that normal tumor suppression functions cannot take place.
Note 2: Other terms for LOH include gene deletion and allelic loss.

Code	Description
010	Test positive for loss of heterozygosity (LOH)
020	Test negative for LOH; normal heterozygous state
030	Undetermined if LOH positive or negative
988	Not applicable: Information not collected for this case (If this information is required by your standard setter, use of code 988 may result in an edit error.)
997	Test ordered, results not in chart
998	Test not done (test not ordered and not performed)
999	Unknown or no information Not documented in patient record

CS Site-Specific Factor 10
18q Loss of Heterozygosity (LOH)