I've never blown-out the last drop of any glass pipette I've ever used during my undergraduate studies. Recently I re-read some notes I had lying around in order to prepare a class I had to give to a group of first year undergraduates and found out that there is a class of glass pipettes which need to be "blown-out" in order to deliver the nominal volume correctly.
I researched a little bit and found what seems to me to be completely inconsistent terminology and conventions to refer to this class of pipettes.
In https://en.wikipedia.org/wiki/Graduated_pipette it is clearly stated that there are "two kinds" of graduated pipettes. "serologic/blow-out" and "Mohr/drain-out". It is also stated that serologic pipettes have calibration marks all the way to the tip, whereas Mohr pipettes do not. The same page states that pipettes are either calibrated "to deliver" (TD) or "to contain" (TC). It states that "TD" is a far more common calibration than "TC" and explains that pipettes calibrated TC need to be blown-out in order to deliver the expected volume correctly, one would assume from this that TD is a synonym fro "blow-out". Judging from this there would seem to be two kinds of pipettes, "serologic/blow-out/TD" and "Mohr/drain-out/TC". This really contradicts my experience, I've been using pipettes with marks going all the way to the tip and never been told to blow out the last drop, however, there is always the chance I've been doing it wrong this whole time.
Digging a little bit deeper I found that this document http://www.brand.de/fileadmin/user/pdf/Information_Vol/Brochuere_Volumenmessung_EN.pdf (link downloads pdf) that wikipedia lists as a source doesn't mention "blow-out" pipettes at all, but does mention pipettes calibrated "TC". In page 13 there are some pictures and descriptions of pipettes resembling what one would think are "Mohr" and "Serologic" types, and both are said to be calibrated "to deliver" actually, reading this text one would think that ALL graduated and volumetric pipettes are calibrated to deliver (however, this document is from a lab equipment manufacturer, perhaps they only manufacture TD pipettes...?).
Digging yet deeper http://faculty.clinton.edu/faculty/Mike.Lawliss/My_webpage/Sci110/Other%20documents/Pipetting%20A%20Practical%20Guide_Guzman2001.pdf is another article cited as a source by wikipedia. Here the author pretty much identifies serologic pipettes with blow-out ones, but also states that blow-out pipettes "usually" have double rings (non-colored) near the top. There is, however, a drawing of a "serologic" pipette WITHOUT rings near the end of the article, close to an "Ostwald-Folin" pipette WITH rings which the author specifically identifies as blow-out. The definition of the term "serologic" pipette is, according to the author, "a type of measuring pipette used to measure variable volumes" which in my view would make ALL graduated pipettes serologic.
To add to all this confusion Sigma-Aldrich seems to manufacture "TD, blow-out, serologic pippetes" http://www.sigmaaldrich.com/catalog/product/sigma/z325422?lang=es®ion=AR and also "TD/TC volumetric pippetes", which makes me lose all hope of making sense of any of the terms listed in the question at all.
In short, is there a STANDARD way in which these terms (TD, TC, IN, EX, Blow-out, Serologic, etc) are used? Is there a standard definition regulated by some sort of organization, or at least generally agreed upon? If you think that there is, could you please provide trustworthy sources? Thanks a lot.
This probably seems like a silly question (it is =D) but it kind of bugs me not to know something so basic as "what are the different kinds of graduated pipettes?"... It seemed like something that would be quite easy to settle when I started looking into it... guess I was wrong.