Source: Luminex Corporation

Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares in Luminex Corporation (LMNX) tumbled by more than 10% today after the company reported solid fourth quarter earnings but issued guidance that fell short of analyst expectations.

So what: Luminex's results were far from disastrous, but they weren't earth-shattering either.

Sales in the quarter improved 5% year-over-year to $58.1 million, and sales for the full year grew 6% to $227 million. Sales growth was most impressive for its test assays that consist of chemical and biological reagents that are used to perform diagnostic and research work on samples in biomedical labs. Assays revenue jumped 34% to $24.1 million last quarter, and that more than offset a 31% slide in system sales to $6.87 million.

Luminex's bottom line performance wasn't horrible either. On a GAAP-basis, earnings per share totaled $0.53 and $0.92 for the quarter and full year, respectively. After adjusting for items, non-GAAP EPS was $0.19 and $0.90 for the two periods, respectively. The non-GAAP results from the same periods in 2013 were $0.21 and $0.62, respectively.

Although the full year financial results mark a significant operational improvement from 2013, investors appear to be focusing predominately on Luminex's expectations for 2015. Luminex estimates that its sales will total between $230 million and $236 million this year. That forecast is below the current consensus Wall Street estimate of $241.46 million.

Now what: Luminex could be sand-bagging its 2015 forecast to provide it with more room to negotiate pricing to drive demand for the two new systems it plans to launch this year. If sales of those systems -- the ARIES and NxTAG -- are solid this year, it could clear the way for additional assay revenue growth in 2016. Regardless, since Luminex sales and earnings continue to grow, and the long term opportunity for genetic testing remains attractive, investors may want to put this company on a list of names to consider.