Quest Diagnostics (NYSE:DGX)Abiomed (NASDAQ:ABMD), and Acceleron Pharma (NASDAQ:XLRN) are trying to improve patients' lives in very different ways, but each could be a top healthcare stock to buy now, according to three Motley Fool contributors. Read on to learn how Quest Diagnostics may benefit from a new exclusivity deal, Abiomed plans to expand the use of its heart pumps to more people, and Acceleron Pharma hopes to improve how doctors treat patients with rare blood disorders.

It's part of virtually every medical encounter

Chuck Saletta Quest Diagnostics: When you're in the doctor's office for a routine checkup, you'll likely have blood and/or other bodily fluids drawn for testing. When you're in there because you're sick, you're almost certain to have tests done. If you ever find yourself on medication for anything, you guessed it -- even more tests to assure everything's working as it should.

A lit-up light bulb on a pile of coins.

IMAGE SOURCE: GETTY IMAGES.

As a strong player in the medical testing industry, Quest Diagnostics gets a decent share of those tests. Because that testing is such a critical part of so many medical procedures, Quest Diagnostics already takes in around $8 billion in annual revenue.

Trading as it does around 14 times its anticipated earnings, Quest Diagnostics already looks like a reasonably priced company. What makes it compelling to consider buying now is that effective in January, Quest Diagnostics will become an in-network provider for all UnitedHealth Group (NYSE:UNH) plans. That expansion gives it the chance to grow even faster.

Quest Diagnostics' earnings are expected to increase by around 8.3% annualized over the next five or so years, a reasonable pace for an already established business. Its shares look fairly valued based on those expectations. That said, if the new partnership with UnitedHealth enables it to deliver at an even faster pace, then today's price could look like a bargain.

The thing is that if this new partnership allows Quest Diagnostics to grow at a faster rate, the market will likely react to learning that news fast. As a result, now -- before any improvements are realized -- is a great time to consider buying Quest Diagnostics shares. If faster-than-expected growth doesn't happen, you're still getting a solid healthcare company at a reasonable price. If it does materialize, you'll be an owner before the market makes its adjustment.

Take the long view

Brian Feroldi (Abiomed): When a healthcare company releases good clinical news, you'd normally expect its stock price to move higher. That's why I was left scratching my head as to why shares of medical device maker Abiomed plunged by double digits after it recently reported upbeat results from an important clinical trial. What gives?

Abiomed announced the results of a safety and feasibility study for patients with anterior ST-segment elevation myocardial infarction. The trial was designed to figure out if it would be safe to clear out a patient's left ventricle with its Impella pump 30 minutes prior to reperfusion. The clear answer from the study was that it was safe to do so and that there may also be a clinical benefit to doing so. In response, Abiomed decided to push forward with a pivotal trial to eventually seek approval.

Sounds good, right? Well, an analyst at Jefferies released a report to his clients soon after the news broke stating that the report was good but "likely not enough to move the stock." Traders decided to thrash the stock in part because of that tepid commentary. The reaction makes some sense when you consider that Abiomed's stock has been red hot and that the company trades at a nosebleed valuation. Even after the plunge, shares are trading at 66 times next year's earnings estimates.

I have no doubt that Abiomed's stock will continue to be volatile, but I can't help but be bullish on this company's long-term potential. The company's revenue and profits are growing at a breakneck pace (they were up 37% and 102%, respectively, in the most recent quarter), and the company has still only scratched the surface of its substantial market opportunity.

While shares of Abiomed are still richly priced, I think this is one of those rare growth stocks that will still perform well for shareholders over the long run in spite of its high valuation. If you agree, buying a few shares on the recent weakness could prove to be a profit-friendly move. 

A scientist looks through a microscope.

IMAGE SOURCE: GETTY IMAGES.

A big win approaching?

Todd Campbell (Acceleron Pharma): In December, Acceleron Pharma and its collaborator Celgene Corp. (NASDAQ:CELG) will present data from successful trials evaluating their beta thalassemia and myelodysplastic syndrome (MDS) drug, luspatercept. The additional data could spark a rally in Acceleron's shares if it supports the thinking that luspatercept will secure a regulatory OK after its makers file for approval early next year.

Acceleron and Celgene already reported positive top-line data from trials in these indications in June, so the presentations should be favorable. At the conference's Plenary Session on Dec. 2, the abstract for luspatercept's MDS trial results will be honored as one of the top six abstracts submitted this year (out of more than 6,500). Meanwhile, the beta thalassemia data will be provided during an oral presentation on Saturday, Dec. 1.

Celgene said earlier this year that it thinks luspatercept could become a backbone therapy used in other anemias, too, and trials are already underway that could increase the drug's addressable market. Overall, Acceleron says that the five indications it's currently targeting represent 120,000 people in the U.S. and Europe.

The companies have set a peak sales target of $2 billion or more annually for the drug, but that doesn't include additional indications that may also be pursued. Assuming regulators green-light luspatercept and their peak sales forecasts are anywhere near correct, Acceleron Pharma could be undervalued. It will split North American sales with Celgene, and it will receive low- to mid-20%-range royalties elsewhere, so it could pocket hundreds of millions in sales -- or more -- annually in revenue if this drug is a success. Since the company's market cap is just $2.3 billion, it has other drugs in its pipeline for other indications that could pan out, and Celgene owns 12.2% of it already, I think picking up shares now is smart.

Brian Feroldi owns shares of Abiomed and Celgene. Chuck Saletta has no position in any of the stocks mentioned. Todd Campbell owns shares of Celgene. His clients may have positions in the companies mentioned. The Motley Fool owns shares of and recommends Abiomed and Celgene. The Motley Fool recommends UnitedHealth Group. The Motley Fool has a disclosure policy.