In the table below you are prompted to identify your problem with the results obtained from the DIAPOPS technique. Every option with a number can be selected. After this selection, a new page will appear showing a list of factors or steps in the DIAPOPS procedure, which could be the cause to the problem selected in the table. From this page it is possible to select one of the causes or steps. Then a new page will turn up with detailed explanations about the step or reagents selected.

In order to give an answer which is as close as possible to the true problem it is necessary to know how the liquid PCR* reactions made in the NucleoLink Strips appear on an agarose gel. It is therefore presumed that the agarose gel analyses have been performed, when the selection is made in the table below. In the selection of the 12 first options in the table it is presumed that there has been no evaporation from the wells during the thermal cycling. For this reason it is very important that the liquid remaining in the wells after thermal cycling is only 5-10 % less than that initially added. Otherwise, the trouble shooting will not be efficient.

Problem	Identification
No DIAPOPS signal above background	PCR bands of expected size and concentration is observed on agarose gel Bands weaker than expected on agarose gel No PCR band at all detected on agarose gel
Poor sensitivity in DIAPOPS (Low signals and/or poor detection limit)	Agarose gel as expected with normal PCR bands, but only reactions with strong PCR bands are detected in DIAPOPS Poor sensitivity (and/or low product concentration) on agarose gel. (DIAPOPS and agarose gel results are similar)
Reproducibility problems in DIAPOPS results	Only DIAPOPS signals lack reproducibility, whereas agarose gel provides good, reproducible results Agarose gel and DIAPOPS results correlate, and both show variable results
Rehybridization problems in the same strip after PCR	DIAPOPS signals increase in subsequent rehybridizations DIAPOPS signals decrease in subsequent rehybridizations
Background problem in DIAPOPS	Agarose gel shows bands from blank samples Agarose gel as expected, and shows no band from blank samples
Evaporation during thermal cycling	All wells show the same degree of evaporation, or, only some wells are empty, or with a visible loss

*The Polymerase Chain Reaction (PCR) process is covered by US patents owned by Hoffmann-La Roche, Inc and F. Hoffmann-La Roche Ltd.