A Google Webmaster Help thread has a suggestion from a webmaster. The suggestion is to add pages blocked in the diagnostic > crawl errors report for pages blocked by the META NOINDEX.

Currently, Google will display pages blocked for multiple of reasons, including restricted by robots.txt but it won’t show the pages blocked by the META NOINDEX tag.

Susan Moskwa, Webmaster Trends Analyst from Kirkland, WA Google office, said:

Useful report to have, so why not add it?

Forum discussion at Google Webmaster Help.