The American Nurses Association, like the American Medical Association, is a national, federated organization, but unlike the AMA, doesn't admit individuals.
The ANA has just 53 members: state nurse associations in the 50 states, plus the District of Columbia, Guam and the Virgin Islands. Individual nurses join their state association and pay dues to it, a portion of which is forwarded to the ANA.
For that reason the ANA doesn't always know exactly how many nurses it represents at any given moment. The association relies on state nurse organizations to keep rosters of individual nurse membership and report those totals to Washington.
There are 1.8 million employed registered nurses in the United States. Of those, about 180,000 are represented by the ANA.
One of the risks of such a federated structure is the loss of membership that follows if a state group disassociates from the national alliance. Last year the California Nurses Association, dissatisfied with the ANA's performance on certain issues, voted to break away from the national umbrella group. When it did so, some 22,000 nurses went with it, along with $1.8 million in dues it had sent to Washington. That constituted a 10% cut in the ANA's annual revenues.
Before the CNA's departure, the ANA represented more than 200,000 nurses.
After the CNA left, the ANA established a new association, ANA/California, for nurses who wanted to maintain links to the national group.