This week, three life science stocks are improving their overall rating on Portfolio Grader. Each of these rates an “A” (“strong buy”) or “B” overall (“buy”).

Quintiles Transnational Holdings, Inc. (Q) ups its rating to a B (“buy”) this week after earning a C (“hold”) in the week before. In Portfolio Grader’s specific subcategories of Earnings Growth, Earnings Momentum, Earnings Revisions, Earnings Surprise and Margin Growth, Q also gets A’s. For more information, get Portfolio Grader’s complete analysis of Q stock.

This week, Covance (CVD) is making solid headway. The company’s rating improves to an A (“strong buy”) from last week’s B (“buy”) rating. Covance is a drug development services company providing a range of early-stage and late-stage product development services to the pharmaceutical, biotechnology, and medical device industries. For more information, get Portfolio Grader’s complete analysis of CVD stock.

Albany Molecular Research, Inc.’s (AMRI) ratings are looking better this week, moving up to a B from last week’s C. Albany Molecular Research provides contract services to various pharmaceutical and biotechnology companies primarily in the United States, Europe, and Asia. Shares of the stock have been changing hands at an unusually rapid pace, four times the rate of the week prior. For more information, get Portfolio Grader’s complete analysis of AMRI stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.