For the first time, the World Health Organization has published a list of diagnostic tests that it considers essential to every health care system in the world.

The list, published Wednesday, is similar to the agency’s essential medicines list, which the W.H.O. launched in 1977.

In its day, the medicines list was revolutionary because it was both a global guide to rational treatment regimens and because it fostered the idea that certain medicines were so important that they should be available to the whole world, regardless of price.

The W.H.O. expert panel that created the diagnostics list hopes it will eventually be just as revolutionary.