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 bettering its rating of C (“hold”) from last week 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. For more information, get Portfolio Grader’s complete analysis of CCRN stock.

Triple-S Management Corporation Class B (GTS) shows solid improvement this week. The company’s rating rises from an A to a C. Triple-S Management is an independent licensee of the Blue Cross Blue Shield Association. Shares of the stock have been changing hands at an unusually rapid pace, twice the rate of the week prior. For more information, get Portfolio Grader’s complete analysis of GTS stock.

Fresenius Medical Care AG & Co. KGaA Sponsored ADR’s (FMS) ratings are looking better this week, moving up to a B from last week’s C. Fresenius Medical Care offers kidney dialysis services and manufactures and distributes equipment and products used in the treatment of dialysis patients. For more information, get Portfolio Grader’s complete analysis of FMS stock.

This week, Bio-Reference Laboratories, Inc. (BRLI) is making solid headway. The company’s rating improves to an A (“strong buy”) from last week’s B (“buy”) rating. 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.

This is a strong week for DaVita HealthCare Partners Inc. (DVA). The company’s rating climbs to B from the previous week’s C. DaVita operates kidney dialysis centers in the United States. 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.