Business continues to boom for many small- and mid-cap diagnostic companies. A prime example of this trend is the blood-testing equipment maker Immucor (NASDAQ:BLUD), which released its first-quarter earnings after the closing bell yesterday.

It was another strong quarter for the company, and its shares have gone up another 9% today. The stock continues to be on an absolute tear. It is up more than 60% over the past 52 weeks. Immucor's Q1 earnings increased by 39% on a 25% increase in sales versus its year-ago quarter.

What is especially striking for investors to note is how the company achieved these strong gains. Despite having a market cap of just over $2.4 billion, the company does have pricing power. About 70% of the Immucor's incremental gains in total sales, when compared with the prior year, came from price increases. This favorable pricing also allowed the company to improve its gross margin significantly -- from 68% to 72%.

It might be seen as a slight risk that only 25% of its incremental gain in sales came from volume improvement, but when a company ratchets up prices considerably, it becomes less of a worry. Not to mention that excluding the price increases, revenues would still be up a respectable 8% year over year.

While Immucor continues to be a strong player in this sector, there are others. Among them are Meridian Bioscience (NASDAQ:VIVO) which continues to turn out record earnings quarter after quarter, and Beckman Coulter (NYSE:BEC), a mid-cap diagnostic company that supplies instrument systems to clinical labs and is up about 30% over the past 52 weeks. Even animal diagnostics have prospered; IDEXX Laboratories (NASDAQ:IDXX), a maker of diagnostic devices used by veterinarians, has produced solid results. Its shares have climbed more than 20% in the past year.

Even if the sight of blood makes you queasy, Immucor is one growth stock with the potential to cure you of that trepidation.

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Fool contributor Billy Fisher does not own shares of any of the companies mentioned. The Fool has a germ-free disclosure policy.