3 Life Sciences Tools & Services stocks are moving up in their overall rating this week, according to the Portfolio Grader database. Every one of these is graded an “A” (“strong buy”) or “B” overall (“buy”).

Mettler-Toledo International Inc. (MTD) improves from a B to a A rating this week. Mettler-Toledo International Inc. supplies precision instruments and services and is a provider of weighing instruments for use in laboratory, industrial and food retailing applications. The company also gets A’s in return on equity. For more information, get Portfolio Grader’s complete analysis of MTD stock.

PRA Health Sciences, Inc. (PRAH) boosts its rating from a B to a A this week. The company also gets A’s in operating margin growth and earnings growth. For more information, get Portfolio Grader’s complete analysis of PRAH stock.

Luminex Corp’s (LMNX) ratings are looking better this week, moving up to a B from last week’s C. Luminex Corp develops, manufactures and markets biological testing technologies with applications throughout the clinical diagnostic and life science industries. The company also gets A’s in earnings growth and free cash flow. For more information, get Portfolio Grader’s complete analysis of LMNX 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.