The study, to be published next week in the Lancet, a British medical journal, found that a new computer-based diagnostic test can accurately distinguish between blood samples from women with ovarian cancer and samples from women without the disease. The test, which recognizes patterns of proteins in blood, was also able to identify the disease in its early stages, when treatment is most effective.

Unlike other types of cancer, there is currently no standard diagnostic test for ovarian cancer for the general population. One test measures a tumor marker called CA 125, but it misses half of all early-stage cancers and 20 percent of late-stage cancers. Another test, the transvaginal sonogram, is expensive, inconvenient and fails to distinguish between benign and malignant tumors.

The researchers then used that protein pattern to classify 116 blood samples that included 50 cancerous samples and 66 non- cancerous samples. The test correctly identified all 50 cases of ovarian cancer and identified 95 percent of the control samples as non-cancerous.