TaqMan™ Rodent MicroRNA A Array v2.0 - FAQs

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18 product FAQs found

Why does the negative control well show amplification when doing microRNA analysis using Megaplex Primer Pools and TaqMan Array Cards?

Most likely the reagents or the cDNA template are contaminated. Please follow established PCR laboratory best practices.

Why do I have poor reproducibility across technical replicates when doing microRNA analysis using Megaplex Primer Pools and TaqMan Array Cards?

Most likely the reagents were not adequately mixed. Ensure that all samples and reagents are mixed well.

When doing microRNA analysis using Megaplex Primer Pools and TaqMan Array Cards, why are the Ct values for the endogenous controls highly variable across the sample set?

Highly variable values for endogenous controls is most likely due to biological variation. We recommend that you use an alternative endogenous control, such as a non-variable miRNA.

Why is the Ct value for the no-template control (NTC) <35 for some TaqMan microRNA Assays?

The Ct value for the NTC can be <35 for the following reasons:
- There are non-specific interactions between primers. For NTC information on a specific assay, see the Megaplex Assay Performance File.
- The cDNA template is contaminated. Please ollow established PCR good laboratory practices to prevent contamination.
- The preamplification product was not diluted properly before real-time PCR. Ensure that you dilute the preamplification product according the procedure in the user guide.

Why can I not detect any miRNA in my sample using the TaqMan MicroRNA Assay?

Most likely, the threshold is set too high to detect miRNA in samples with low levels of expression. We recommend adjusting the threshold (Ct) or NOAMP flag threshold (Crt) to an appropriate level.

Why is the baseline variable when doing microRNA analysis using Megaplex Primer Pools and TaqMan Array Cards?

Most likely the dried-down assays on the card were reconstituted at different rates, causing a dip in the early cycles of the baseline. We recommend that you use the relative threshold algorithm (Crt), which can correct for a variable baseline. If the software specific to your instrument does not have the relative threshold algorithm use the Relative Quantification app on Thermo Fisher Connect.

When doing microRNA analysis using Megaplex Primer Pools and TaqMan Array Cards, why do my technical replicates have poor precision (standard deviation >0.5 for assays with a Ct value <30)?

Please review the following possible causes and solutions:
- Bubbles in wells. Use proper pipetting techniques to avoid introducing air into the fill reservoirs. Consider omitting the leaking wells from analysis.
- Wells leaking due to improper card sealing. When sealing the card, use a slow and steady motion to push the carriage across the TaqMan Array Card Sealer. We recommend that you consider omitting the leaking wells from analysis.
IMPORTANT: Do not move the carriage back across the card.
- Not all of the positions in the card holder were filled before centrifuging. Ensure that all of the empty positions of the card holder are filled with blank balance cards before centrifuging.
- The cards were centrifuged using a non-verified centrifuge. We recommend that you use a Sorvall centrifuge to prepare cards. Please see the Resources section at thermofisher.com/taqmanarrays for a list of compatible centrifuges.
- The dried-down assays on the card were reconstituted at different rates, causing a dip in the early cycles of the baseline. We recommend that you analyze results with the relative threshold algorithm (Crt) instead of the baseline threshold algorithm (Ct).

When doing microRNA analysis using Megaplex Primer Pools and TaqMan Array Card, why is there no amplification within or across one or more rows of the card?

Please review the following possible causes and solutions:
- Empty wells due to improper card sealing. When sealing the card, use a slow and steady motion to push the carriage across the TaqMan Array Card Sealer. Do not move the carriage back across the card.
- Empty wells due to misalignment of the TaqMan Array Card Sealer. If the TaqMan Array Card Sealer is misaligned, contact Support.
-PCR reaction mix improperly prepared. Ensure that all reaction components were added to the PCR reaction mix.

When doing microRNA analysis using Megaplex Primer Pools and TaqMan Array Card, why is there no amplification in some wells?

Usually, empty wells are due to improper card sealing. When sealing the card, use a slow and steady motion to push the carriage across the TaqMan Array Card Sealer. Do not move the carriage back across the card.

When doing microRNA analysis using Megaplex Primer Pools and TaqMan Array Card, why is there no amplification for portions of the card?

Most likely the card was misaligned in the block during the instrument run. Inspect the card for crushed or distorted feet. If there are damaged feet, contact Support.

When doing microRNA analysis using Megaplex Primer Pools and TaqMan Array Cards, why is there noise in the amplification plots for portions of the card?

Most likely the card was misaligned in the block during the instrument run. Inspect the card for crushed or distorted feet. If there are damaged feet, contact Support.

Why is the fill reservoir of my TaqMan Array Card for microRNA analysis completely empty?

Most likely some wells were filled improperly. You can continue with running the card. However, we recommend that you consider omitting the wells associated with that fill reservoir.

Why does the PCR reaction mix remain in a fill reservoir of my TaqMan Array Card for microRNA analysis?

Please review the following possible causes and solutions:
- The filling is incomplete or not consistent. We recommend that you centrifuge the card again for 1 min. If the filling is still incomplete after the additional centrifuge cycle, continue with running the card. However, we recommend that you consider omitting the wells associated with that fill reservoir.
- The fill port is blocked. A blockage is rare. Inspect the card for a blocked fill port or a pinched channel. If the fill reservoir is defective, contact Support.

Why do the fill reservoirs of my TaqMan Array Card for microRNA analysis have bubbles in the PCR reaction mix?

Most likley when loading the card with PCR reaction mix, air was introduced into the fill reservoir. Inspect the affected rows after centrifuging and sealing the card and note wells that contain bubbles. We recommend omitting these wells from analysis.

Why does the PCR reaction mix leak from the vent port into the fill reservoir of the my TaqMan Array Card for microRNA analysis?

The PCR reaction mixture was not correctly pipetted into the fill reservoir. Ensure that you correctly pipette the entire PCR reaction mixture (100 µL) into the fill reservoir. If needed, add more sample‑specific PCR reaction mix to the fill reservoir.

Why is the fill reservoir not full of PCR reaction mix in my TaqMan Array Card for microRNA analysis?

This indicates that the PCR reaction mixture was not correctly pipetted into the fill reservoir. Ensure that you correctly pipette the entire PCR reaction mixture (100 µL) into the fill reservoir. If needed, add more sample‑specific PCR reaction mix to the fill reservoir.

Why does water condense on the reaction wells of my TaqMan Array Cards for microRNA analysis?

This indicates that the card was not at room temperature before being removed from the packaging. We recommend that you remove condensation on the reaction wells by lightly blowing room temperature pressurized nitrogen or using an air blower on the wells.
IMPORTANT: Ensure that all water condensation is removed. The optical side of the card must be free of water condensation.

When doing microRNA analysis using Megaplex Primer Pools and TaqMan Array Cards, why is there gradient signal across the card?

This gradient signal indicates that the card was in a diagonal position during centrifugation because not all of the positions in the card holder were filled. We recommend that you repeat the assay with a new card and ensure that all the positions in the centrifuge card holder are filled.