Shares of Chemed ( CHE) were among the worst-performing health-related stocks Friday, falling 7% after the company said that its Vitas Healthcare business is being investigated by the Department of Health and Human Services. The company said the civil investigation relates to Vitas' "alleged failure to appropriately bill Medicare and Medicaid for hospice services." As part of its investigation, the Office of Inspector General is reviewing 80 sets of records each from Vitas' three largest programs. Additionally, it is looking at another 80 records that it selected from other programs. The patient records span from 1997 to present. Chemed said the investigation looks similar to a previous industrywide OIG investigation. At the time, the OIG inspected records from 1995 to 1998. Ultimately, no adverse actions were taken against the company, Chemed said. Shares were trading down $5.30 to $71.11. Cardima ( CRDM) fell 10% after its auditor expressed doubt about its ability to continue as a going concern. The medical equipment maker said that similar language has been included in the company's annual reports during the past three years. Cardima said that recurring losses and a net capital deficiency led to the auditor's conclusion. At the end of March, the company had $1.7 million in cash and cash equivalents, which the company believes will not be sufficient to fund operations beyond the third quarter. As a result, the company is exploring potential funding opportunities that include a strategic transaction or stock sale. Shares were trading down 2 cents to 19 cents. Shares of Misonix ( MSON) fell 11% after the company cut its earnings outlook and narrowed its sales range. The medical device maker now expects 2005 earnings to be similar to 2004 results. Sales, meanwhile, are now expected to grow by 12% to 15%. Previously, the company said that it would post earnings growth of 25% to 30% on sales growth of 10% to 15%. Order delays, increased spending on marketing plans and technical and production issues surrounding the company's neuroaspirator led to the revised outlook. Shares were trading down 62 cents to $5.21.