This was the stock's fourth consecutive day of gains.

Quest Diagnostics (NYSE:DGX – Get Free Report) was upgraded by Leerink Partnrs from a “hold” rating to a “strong-buy” rating in a report released on Monday,Zacks.com reports. A number of other equities research analysts also recently weighed in on the company.

Shares of Quest Diagnostics Inc. DGX inched 0.23% higher to $152.27 Monday, on what proved to be an all-around mixed trading session for the stock market, with the S&P 500 Index SPX rising 0.55% to 5,