1 EXHIBIT 21 SUBSIDIARIES OF REGISTRANT STATE OF INCORPORATION SUBSIDIARY OR ORGANIZATION - ---------- ---------------------- Health Data Sciences Corporation* Delaware IIH, LLC Delaware Knowledgeable Healthcare Solutions, Inc. Alabama Per-Se Transaction Services, Inc.* Indiana PST Emergency Medicine Services, Inc.* Georgia PST Products, Inc.* California PST Services, Inc.* Georgia - -------------- * Each of these subsidiaries also does business under the name "Per-Se Technologies."