Objective: PAPP-A is a promising new marker in coronary heart disease. It is important to investigate its specificity in order to establish its clinical utility as a marker of coronary heart disease. Design and methods: PAPP-A was measured within 24 h following hospital admission in 1448 consecutive patients admitted with diagnoses other than acute coronary syndromes. Results: PAPP-A was detectable (≥ 4.0 mIU/L) in 278 (19.2%) patients, among whom the mean level was 6.3 mIU/L (95% C.I., 6.1-6.5 mIU/L). The 95 and 99 percentiles for PAPP-A were 7.3 and 9.4 mIU/L, respectively. There was no difference in the mean PAPP-A of different diagnoses (p = 0.33). None of the specific diagnoses known to influence established coronary markers appeared to influence the level of circulating PAPP-A. Conclusion: PAPP-A is low in patients without known coronary heart disease. PAPP-A levels seem to be a potentially highly specific marker for heart disease.