This week, five health care provider stocks are improving their overall rating on Portfolio Grader. Each of these rates an “A” (“strong buy”) or “B” overall (“buy”).

Cross Country Healthcare, Inc. (CCRN) is bumping up its rating from a C (“hold”) to a B (“buy”) this week. Cross Country Healthcare provides healthcare staffing and outsourcing services to the healthcare market. In Portfolio Grader’s specific subcategories of Earnings Momentum, Earnings Surprise and Sales Growth, CCRN also gets A’s. Shares of the stock have been changing hands at an unusually rapid pace, three times the rate of the week prior. For more information, get Portfolio Grader’s complete analysis of CCRN stock.

This week, Triple-S Management Corporation Class B (GTS) pushes up from an A to a C rating. Triple-S Management is an independent licensee of the Blue Cross Blue Shield Association. For more information, get Portfolio Grader’s complete analysis of GTS stock.

The rating of Fresenius Medical Care AG & Co. KGaA Sponsored ADR (FMS) moves up this week, rising from a C to a B. Fresenius Medical Care offers kidney dialysis services and manufactures and distributes equipment and products used in the treatment of dialysis patients. Shares of the stock have been trading at an exceptionally rapid pace, up threefold from the week prior. For more information, get Portfolio Grader’s complete analysis of FMS stock.

This week, Bio-Reference Laboratories, Inc. (BRLI) is showing good progress as the company’s rating jumps from a B (“buy”) last week to an A (“strong buy”). Bio-Reference provides laboratory testing services, primarily to customers in the greater New York metropolitan area. For more information, get Portfolio Grader’s complete analysis of BRLI stock.

DaVita HealthCare Partners Inc.’s (DVA) ratings are looking better this week, moving up to a B from last week’s C. DaVita operates kidney dialysis centers in the United States. Shares of the stock have been trading at an exceptionally rapid pace, up 512.8% from the week prior. For more information, get Portfolio Grader’s complete analysis of DVA 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.