Northfield's stock tanks on blood test results

Shares of Evanston-based Northfield Laboratories Inc. [NFLD] lost more than half their value today after the company announced disappointing results in tests of its experimental blood substitute.

An analyst quoted by the Chicago Tribune called the test results "a disaster." The New York Times described the results as mixed.

In the overall experimental group, more patients given Northfield's PolyHeme blood substitute died than those given a conventional saline solution, although Northfield said that in a subgroup where all test protocols were followed the results were roughly equivalent.

Northfield's chairman said the company plans to go forward with efforts to get the Food and Drug Administration to approve the product.