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Hold SNP Array

Item Value
Approval req'd? Yes, if not ordered by Genetics, Neurology or Neonatal Intensive Care Unit faculty or fellows. Requests on inpatients require approval from
Cytogenetics/Array staff. Insurance authorization required for outpatients.
Available Stat? No
Utilization Guidelines Tests with long turn-around times (ie. Molecular based tests and Microarrays) should only be requested on an inpatient if the result is going to affect the inpatient management.
If the patient will likely be discharged before the result will be available, the test should be requested after discharge. (NOTE: UCSF Medical Center is not reimbursed for inpatient testing).
An exception to the above may be appropriate if there is a possibility the patient will not survive to be discharged and the information is important for diagnosis and/or family decisions/management (ie. recurrence risk).
Test code HSNPA
Test group Microarray
Performed by Medical Genomics - Cytogenetics (Microarray)
In House Availability N/A
Method N/A
Collection Instructions Insurance pre-authorization required for outpatients

Only collect samples Monday - Friday and avoid holidays.

Do not collect sample in lithium heparin (Lt. Green top).

Transport sample at room temperature as soon as possible to lab. If transport is delayed refrigerate sample.

For UCSF Samples (from remote sites) Click here for sample collection instructions

For NON-UCSF Samples Click here for Requisition form & Account set-up instructions. Note we only do institutional billing.

Note: Samples will only be held for 2 weeks pending insurance authorization.
Container type Lavender top preferred, Dark Green top acceptable
Amount to Collect
Adult 5 mL blood
Infant/child 3 mL blood
Sample type EDTA or Heparinized whole blood, Extracted DNA
Preferred volume
Adult 5 mL whole blood
Infant/Child 3 mL whole blood
Extracted DNA 10 µg (mcg)
Min. Volume
Adult 2 mL whole blood
Infant/Child 2 mL whole blood
Extracted DNA 10 µg (mcg)
UCSF Rejection Criteria Unlabeled sample, insufficient sample, clotted samples, samples received in Lithium-heparin (Lt. Green top)
Processing notes Refrigerate samples DO NOT CENTRIFUGE OR FREEZE. Transport asap to China Basin Cytogenetics

For questions, contact the microarray laboratory at 514-8964
Normal range Normal
Synonyms Hold for authorization; Hold for approval; Hold for insurance authorization; Hold for insurance approval; Microarray
Stability Room temperature 4 days, refrigerated 2 weeks.
Additional information The sample will be retained for two (2) weeks from the time of collection pending receipt of the payer authorization. If authorization is not received by the laboratory in that time frame the sample will be discarded.

This test should be ordered only when:
(1) The patient is present to have their sample collected and it would be problematic for the patient to return AND there has not yet been authorization received from the patient's insurer that they will reimburse for a SNP array to be performed.
(2) If routine chromosome analysis is desired prior to performing the array as this will obviate the need to collect another sample for array testing.

For questions, contact the microarray laboratory at 514-8964

Microarray results are reported based on the human genome build 19 (hg19/GRCh37). Cases prior December 1st, 2011, were reported based on hg18/NCBI36. Which human genome build is used must be noted when looking up regions in publicly available databases.

Limitations
Genomic aberrations that may not be detected by SNP array assay include:
- Balanced rearrangement (i.e. balanced translocation, insertion or inversion) and tetraploidy resulted from endoduplication.
- Low level (<30%) mosaicism for unbalanced rearrangements and aneuploidy
- Nucleotide sequence changes (i.e. point mutation or small insertion/deletion below the level of detection or cut-off thresholds)
Imbalances of regions not represented on the array
- Genomic changes in mixed samples (i.e. prenatal samples with maternal cell contamination)
LDT or Mod FDA? N/A
Last Updated 6/25/2015 11:00:31 AM
Entry Number 1632
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