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HelpTest Code LAB3682 Proband Control
Clinical System Name
Proband Control
Description
This request is appropriate when a positive control sample is needed to complete testing of parents and siblings of an individual (the proband) with an uncertain or abnormal result by traditional cytogenetic testing (karyotype, FISH) or chromosomal microarray (SNP microarray, array CGH). Based on the results of the proband's inital testing, one of the following cytogenetic follow-up tests can be performed: SNP microarray, interphase or metaphase FISH, qPCR, or limited karyotype. The appropriate follow-up test is typically indicated on the proband's test report, as is the requirement for an additional sample to be used as a positive control from the proband.
Please contact the Laboratory Genetic Counselors (206-987-5400, labgc@seattlechildrens.org) if you have questions.
Sample Requirements
Specimen: Whole Blood
Container(s): Lavender/EDTA AND Dark Green/Sodium Heparin (no serum separator)
Preferred Vol: 3 mL PER tube (both lavender and green are REQUIRED)
Minimum Vol: 2 mL (1 mL for infants <24 months) PER TUBE (both lavender and green are REQUIRED)
Note: For patients who have had a whole blood transfusion, wait 10 days post transfusion to draw for Cytogenetics. No wait time is necessary if the patient received red cells or plasma.
DNA is not an acceptable specimen type for many Family Study tests, exceptions may be reviewed & approved by the Lab Genetic Counselors.
Processing Instructions
Reject due to: Plasma separator tubes are NOT acceptable.
Spin: N
Aliquot: N
Temp: RT
Storage location:
- Days: Monday-Friday, 07:00-17:00, transport specimen, a copy of the requistion (if the order was transcribed from a paper req), and labels to 4th floor Cytogenetics (station #181).
- Eves/Nights/Weekends/Holidays: Store specimen, a copy of the requistion (if the order was transcribed from a paper req), and labels in the Cytogenetics room temp box in CPA.
Off-site collection: Keep sample at room temperature. Transport to Seattle Children's Lab promptly. Samples received after 3 pm will be set up the following day.
Stability
| Temperature | Time |
|---|---|
| Room temp | 3 days |
| Refrigerated | No |
| Frozen | No |
Availability
See specific Family Study test for estimated turn around times of results. No proband test report will be issued.
Performing Laboratory
Seattle Children's Hospital
Department
Department: Cytogenetics Laboratory
Phone number: 206-987-3961
Department: Molecular Genetics Laboratory
Phone number: 206-987-3872
Lab Client Services: 206-987-2617, labclientservices@seattlechildrens.org
Lab Genetic Counselors: LabGC@seattlechildrens.org
CPT Codes
Please contact the Laboratory Genetic Counselors (206-987-5400, labgc@seattlechildrens.org)
Methodology
Method: see specific Family Study test
Clinical Utility
Chromosomes are the packages within cells that contain a person’s genetic information (called “genes” or “DNA”). This genetic information tells a person’s body how to develop and function properly. Gains (duplications) or losses (deletions) result in extra or missing copies of genetic material. These types of changes in a person’s chromosomes may be associated with known genetic conditions or may cause problems with health and development, such as birth defects or cognitive impairment.
When testing of parents and siblings of a child (the proband) with an uncertain or abnormal result by traditional cytogenetic testing (karyotype, FISH) or chromosomal microarray (SNP array, array CGH) is requested it is sometimes necessary to use a sample from the proband as a positive control during testing.
Based on the results of the proband's initial testing, one of the following genetic follow-up tests can be performed: SNP microarray, interphase or metaphase FISH, qPCR, or limited karyotype.
Requisition
Special Instructions
Test request form should be completed by the ordering physician to include the name of the family member being tested and designate the familial relationship to the proband. Please provide a copy of the family history (pedigree) if available (Cytogenetics Laboratory Fax # 206-987-3840). Follow-up test options (recommendations are listed in the proband's report) are SNP microarray, FISH, limited karyotype, qPCR, or as determined by the Cytogenetics Laboratory.