Applied Biosystems 7900HT User Manual page 175

Applied Biosystems 7900HT Fast Real-Time PCR System and SDS Enterprise Database User Guide
3. Screen for Unknown samples that failed to amplify:
a. In the Allelic Discrimination Plot, select the NTC cluster.
The SDS software highlights the datapoints within the allele plot and the
plate grid.
b. In the plate grid, check the wells containing Unknown samples for selected
wells that clustered with the NTCs.
Samples that clustered with the No Template Control wells may:
• Contain no DNA
• Contain PCR inhibitors
• Be homozygous for a sequence deletion
4. Retest any samples that did not cluster tightly or clustered with NTCs to
confirm the results.
5. If evaluating for multiple markers, do the following:
a. In the Marker drop-down list, select a different marker.
b. Repeat steps 1 through 4
c. Repeat steps a and b until the calls for each marker have been verified.
Calling and Scrutinizing Allelic Discrimination Data
for the new marker.
DRAFT
September 1, 2004 11:39 am, CH_End-Point.fm
NTC cluster
(selected)
No Template
Control wells
Unknown samples
clustered with the NTCs
5-17