The potential to revolutionize healthcare offers investors a significant opportunity to profit from buying top stocks. While there are many healthcare stocks that growth investors can consider, I suggest looking at Illumina (NASDAQ:ILMN), Centene Corp. (NYSE:CNC), and DexCom (NASDAQ:DXCM). Read on to find out how the potential to discover new drugs, provide healthcare to more people, and transform diabetes treatment could make these must-own stocks in growth portfolios.

No.1: A gene-sequencing powerhouse

Trying to unlock the secrets held within human DNA is leading to a rapidly expanding knowledge of what causes genetic diseases. As a result, spending on gene-targeted drug therapies is soaring.

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Investing in the companies that are making these next-generation drugs can be profitable, but it might be even more rewarding to invest in Illumina, because it's the gene sequencing company behind most of these discoveries.

Illumina's installed more than 11,000 of its gene sequencing systems worldwide, and those machines have performed about 90% of all genetic sequencing done to date. Sales of its systems and the consumables used in gene sequencing have it on pace to deliver over $3 billion in sales and between $5.70 and $5.75 in non-GAAP earnings per share (EPS) this year, up from $2.75 billion in sales and $4 in non-GAAP EPS in 2017.

The future, however, could be even brighter following Illumina's decision to acquire the long-read gene sequencing company Pacific Biosciences earlier this month.

In the past, Illumina owed its success to dominating the market for short-read sequencing, which is faster and cheaper but less precise than long-read sequencing. However, demand for long-read sequencing is expected to grow significantly as prices drop and the need for more comprehensive DNA insight increases.

PacBio thinks the long-read market alone could grow from $660 million to $2.5 billion by 2022. If that's the case, then acquiring PacBio's long-read sequencing expertise will pay off handsomely for Illumina investors.

No. 2: An election-night winner

Traditional commercial health insurers have struggled to turn a profit with Obamacare, but that hasn't been the case for Medicaid insurers, including Centene. They know how to serve patients who have more complex and costly healthcare needs.

By leveraging its low-cost experience, Centene's been able to successfully enter markets that traditional health insurers have exited. As a result, Centene's Obamacare exchange membership grew 49% in the past year, to 1.5 million.

At the same time, Centene has taken advantage of Obamacare's Medicaid expansion rules, acquiring competitors and entering new markets. This has increased its Medicaid membership 22% in the past year, to 8.7 million.

The membership growth because of these tailwinds resulted in Centene's revenue climbing 36% year over year, to $16.2 billion, and earnings per share climbing 33%, to $1.79 in the third quarter. However, better days could be coming because Centene's offering Obamacare plans in four new states in 2019 and it recently acquired Fidelis, a New York insurer that's expected to add $11.5 billion in revenue and $500 million in adjusted EBITDA to its financials.

The big risk to this company's growth would be Obamacare's repeal, but that's become unlikely since Democrats won control of the House of Representatives earlier this week. Overall, I think Centene has become one of the most interesting health insurers investors can own following the midterm elections.

No. 3: A data-driven diabetes player

There are 30.3 million Americans with diabetes in America, according to the Centers for Disease Control (CDC), including over 1 million people with type 1 diabetes who require the administration of insulin multiple times daily. In the past, diabetics requiring insulin had to rely on finger sticks and glucose monitors to measure their blood sugar four to 10 times a day, but DexCom's continuous glucose monitors (CGMs) are changing that.

DexCom's CGM is a wearable sensor that measures blood sugar and reports it to devices, including smartphones, and allows patients to have real-time insight into their glucose levels, including blood sugar trends. Importantly, its CGM can alert patients to dangerous glucose readings that can be life-threatening, and because these devices can keep patients within their desired blood sugar range more effectively, patients may experience healthier outcomes.

These advantages have translated into significant growth, including a 45% year-over-year increase in sales, to $267 million, and a year-over-year improvement in earnings per share, to $0.17 from a loss of $0.25 in the third quarter.

The company's sales and profit could accelerate from here, though, because of next-generation automated insulin-delivery systems that rely upon DexCom's technology. For example, Tandem Diabetes (NASDAQ:TNDM), a leading maker of wearable insulin pumps, recently launched a system that integrates its pump with DexCom's CGM to automatically dose insulin based on real-time blood sugar levels. Systems like Tandem's could revolutionize treatment for diabetics, and since the diabetes population is expected to exceed 50 million in the U.S. by 2030, there should be plenty of growth opportunity ahead for DexCom. 

It's anyone's guess what the future may have in store for these companies, but I think the potential to help develop new gene therapies, serve more people with health insurance, and eliminate finger sticks forever make Illumina, Centene, and DexCom compelling stocks to buy now.

Todd Campbell has no position in any of the stocks mentioned. His clients may have positions in the companies mentioned. The Motley Fool owns shares of and recommends Illumina. The Motley Fool recommends Pacific Biosciences of California. The Motley Fool has a disclosure policy.