Sequenom (Nasdaq: SQNM) is getting all its ducks in a row in preparation for launching its SensiGene Trisomy 21 laboratory-developed test. The company announced yesterday that it had set up a supply agreement to buy sequencing equipment and the reagents to run them from Illumina (Nasdaq: ILMN).

I've been fairly hard on Sequenom -- rightfully so, given its history. Clearly, a test that can detect Down syndrome using maternal blood is a lot safer than an amniocentesis. But to convert doctors, the sensitivity and specificity of the test have to be high enough to justify its use. Unfortunately, we don't have that data yet.

It's safe to assume that Sequenom's executives have seen it, though. The trial was completed a couple of months ago, and they're just waiting for the principal investigators to get the data written up and accepted into a scientific journal.

You can look at the deal with Illumina in one of two ways: Either the company is confident that the data will support sales of the test, or management is going with the if-you-build-it-they-will-come model, which works better for fictional baseball fields than for medical products. The size of the deal might have given some clues as to which one was more likely, but the financial terms of the agreement weren't disclosed.

The two companies plan to move the test toward regulatory approval, which should give investors confidence that the data might be fairly positive. Sequenom can sell the test without FDA approval as long as it's running the test in-house, but if it were to gain in popularity, Sequenom would want diagnostics companies with broader reach, such as Laboratory Corporation of America (NYSE: LH) and Quest Diagnostics (NYSE: DGX), to be able to run the test. If you assume Illumina has seen the undisclosed data, there's little reason for the company to spend time helping gain FDA approval if it's unlikely the test will ever move beyond Sequenom, where it already has a supply agreement.

Let's call yesterday's announcement mildly positive for Sequenom, but I'm still taking an if-you-publish-it-I'll-consider-investing attitude.

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Fool contributor Brian Orelli holds no position in any company mentioned. Check out his holdings and a short bio. Motley Fool newsletter services have recommended buying shares of Quest Diagnostics, Laboratory of America Holdings, and Illumina. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.