Little details that molecular biology kit makers don’t tell you.?

Question

What are some of the problems that you have noticed with kits that are supposed to make molecular biology procedures go faster or easier than the traditional method? I’ve had multiple problems with kits that promise “Rapid” results, yet require tweaking (naturally omitted from the product brochure). Normally, I get the necessary information either by trial and error or by consulting discussion boards online. This is BS that we pay so much money for these kits to make our lives easier and our research move along faster, yet we experience multiple failures before finding the simple modification that makes the product work as promised.

Answer 1

Pretty much every kit is going to need "tweaking", that's why you are supposed to validate every new procedure before actually using it.  Every instrument is different and that can affect the results.  Even something like the temp in your lab can.  

The kits are still much faster and cheaper than doing everything the "long way".  For example, instead of spending weeks or months figuring out a multiplex, you can use a kit.

Answer 2

It's true that kits often require tweaking to get optimal results, but they usually beat the traditional methods hands down for both speed and repeatability (i.e. Using spin column kit for plasmid isolation beats boiling mini-preps any day of the week).

The trick I find is to understand what each component does, so you can think through a problem and know how to adapt the kit to your use. The problem with kits is they try to be all things to all  people. If your situation requires you to differ from the established protocol, you will have problems. A few years back I had problems using a Qiagen kit to isolate plasmids. The kit suggested DH5A as the ideal cell type, but I was using HB101. In theory there should be no difference: the two cell strains are both E.coli and differ only by a few alleles, but my yield doubled when I switched to using DH5A.

I've noticed that with glass milk based DNA purification kits the DNA you get sucks if you are planning on doing a digestion, ligation, or sequencing.

I've used the Qiagen spin column kits (from mini-prep to giga-prep) for DNA isolation and got great results, but learned to pre-heat the elution buffer to 37C to maximize yield.

When using spin column kits to isolate DNA from organs that are full of connective tissue, like liver, I've learned that you can use a syringe to apply pressure to the column and force the lysis buffer through, otherwise it will clog.

These tricks exist for every kit I suspect. My best advice is before you use a new kit go talk to someone else in another lab who has used it and see if they have any advice. If no-one around you has tried it pressure the sales-rep for free samples so you can optimize the reactions without spending grant money.