| 436 / | HD | CHEMISTRY: ANALYTICAL AND IMMUNOLOGICAL TESTING |
| 91 | DF | HETEROCYCLIC CARBON COMPOUND (I.E., O, S, N, Se, Te, AS ONLY RING HETERO ATOM) {3} |
| 96 | DF | .~ Hetero-N {2} |
| 98 | DF | .~.~ Plural nitrogen in the same ring (e.g., barbituates, creatinine, etc.) {1} |
| 99 | | .~.~.~ Uric acid |