Along with a 223-page instruction manual, the NIH offers gems like this to help clear up the confusion:

# What part of the application/award number is the IC and serial number?
NIH's grant application/award numbers consist of the following parts:

* A single-digit Application Type
* A three-digit Activity Code
* A two-letter IC Code
* A six-digit Serial Number
* A two-digit Grant Year (preceded by a dash to separate it from the serial number)
* Additional suffix information that may include the letter "S" and related number for a particular supplement record, the letter "A" and related number to identify an amendment and/or the letter "X" and related number to identify a fellowship's institutional allowance record.

For example, 3R01CA123456-04S1A1 would indicate an amendment (A1) to a supplemental (Type 3) application for a traditional research project (R01) referred to the National Cancer Institute (CA). The number further identifies the application serially as the 123456 new proposal submitted to the NCI, and indicates that this is the first supplemental application (S1) to the fourth year (-04) of the support to this project. In this example, the IC and serial number would be "CA123456".

Additional information on the NIH grant application/award identification numbering system can be found at: (PDF - 622 KB).

Recently, the NIH switched from paper to electronic grant application submissions. In an amazing feat of ingenuity, I think they managed to make electronic submission more difficult than paper submission.

This logo is totally appropriate: