Have you ever submitted a DNA sample and received notification that the sample failed testing and was reported as a no results(NR)? GeneSeek, Inc. has supplied ASA with the most common reasons samples fail testing and yield an NR.
- Biological Contamination
a. Cross contamination between samples/animals
b. Fecal matter and dirt in sample – any foreign material in the sample may interfere
- Chemical Contamination
a. Dye/Pigment from animal markers
b. Insect repellent
c. Cleaning agents
- Improper Storage
a. Heat exposure including leaving samples in vehicle or in hot sun.
b. Exposure to foreign material including mold
c. Improper frozen storage – the freeze/thaw cycle of a self-defrosting unit can
d. Extended sample storage – DNA degrades over time
- Insufficient sample
- Improper shipping
Concerns Specific to Sample Type
1. Insufficient blood spotted on card – ensure the circle is filled and the blood is visible on
both sides of the paper.
2. When spotting cards from stored blood, make sure to invert the tubes 4-5 times before
spotting – blood settles/separates over time.
3. Do NOT speed-dry the card using a hair-dryer as heat may damage the DNA.
1. Too few or no follicles (<30) – DNA only occurs in the ‘root’ of the hair. The actual
strands do not contain DNA.
2. Small follicles taken from young calves – hair samples should not be taken from calves <
6 months of age.
1. Store any semen samples at room temperature or a refrigerator.
2. Semen straws can easily be damaged in shipping. Proper packaging is especially
important – an empty ball point pen tube is recommended packaging.
Keep in mind, approximately 3% of samples fail testing and are reported as an NR. Plan ahead and submit samples at least 8-12 weeks prior to needing the results, that way if a sample fails testing you have time to submit a second sample before results are absolutely needed. If you have additional questions email firstname.lastname@example.org or call our office at 406.587.4531.