Heartland Assays began as a joint venture between Dr. Ronald Horst and Dr. Bruce Hollis. Over the past 40 years, Dr. Horst and Dr. Hollis have become instrumental at development and application methodologies to assess Vitamin D status and supplement/food integrity. Vitamin D assays have been conducted on a wide range of species including, but not limited to, human, porcine, bovine, murine and avian. Heartland Assays has provided analytical services for many large scale projects including the USDA National Food and Nutrient Analysis Program (NFNAP) and the Cohort Consortium Vitamin D Pooling Project of Rarer Cancers (VDPP), which brought together 10 cohorts for a prospective study on the association between Vitamin D status, measured as serum concentrations of 25-hydroxyvitamin D (25(OH)D), and the development of seven rarer cancers (endometrial, esophageal, gastric, kidney, non-Hodgkin lymphoma, ovarian, and pancreatic).

Heartland Assays mission is to provide analytical services for research and industry (and soon to be clinical) clientele, and help them assess and evaluate Vitamin D status. With cutting edge technology and over 60 years of combined experience, Heartland Assays has the knowledge, skills and expertise to provide a "one-stop shop" for all of your Vitamin D and Vitamin D related needs.


Dr. Ronald Horst

Dr. Bruce Hollis