SalEst' Test for Preterm Labor

August 18, 2006

From ACOG - Philadelphia, Pennsylvania - May, 1999

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Ada Popek: "Hello, my name is Ada Popek, and I'm with a company by the name of Biex. We're a relatively new young company out of California that has developed a new technology for assessing patients at risk for preterm labor. With me I have Dr. McGregor, who is with the University of Colorado. Doctor, can you tell us a little bit about the test and how you're using it in your hospital system?"

Dr. McGregor: "Sure Ada. The test is called 'SalEst,' short for salivary estriol. It's collected in saliva, which is a painless way to collect hormonal measurement, and it measures estriol. Estriol is a hormone that's produced by the baby and the placenta. Estriol measurement is actually a way to tell what time it is on the placental clock, and women themselves can actually plot how their pregnancies are doing in terms of getting the signal to go into labor, and this is done painlessly. We ask women to actually measure their salivary estriol themselves once a week, and we plot the results. It's really fascinating, and patients really appreciate knowing when their clock is about to go off."

Ada Popek: "What gestational age do you begin using SalEst?"

Dr. McGregor: "We actually begin at 24-weeks gestation and measure every other week, but I think actually the most information we can get starts at 28- to 34-weeks. Many of our patients and their families want to know when the clock goes off, so they're actually anxious to get the test every week, even after 34 weeks."

Ada Popek: "Doctor, which patients do you think the test is most valuable for?"

Dr. McGregor: "I think it's valuable for everyone because we're really looking at the natural signal that the placenta and the baby give to make the mother's uterus go into labor and, actually, this is valuable information for everyone. I think the focus in medicine will be to apply it to patients who are at high risk, who've had a prior preterm birth before, or who have twins or other kinds of problems. But in fact, this is a everday test looking for the natural signal of labor and birth."

Ada Popek: "Do you find that the patients are really compliant and accept this test easily?"

Dr. McGregor: "Yes, Ada. The test is simple. There's no vena-puncture, there's no pain, and actually, its just sort of collecting saliva. Pregnant women often times have a lot of saliva-in medicine we call that 'ptyalism,' and it makes it very easy to collect this test. It's not gooey, it's not messy, and it doesn't even have to be refrigerated. You just simply seal it in a little plastic container and mail it off."

Ada Popek: "How long is it before the results are forwarded to the physician?"

Dr. McGregor: "The results come overnight by U.P.S. Actually, the results are done by 10:30 the next morning, and they get faxed or e-mailed to us."

Ada Popek: "At that point the doctor would use the results, I assume, to determine a pathway or treatment for the patient?"

Dr. McGregor: "Yes, if there's a concern about preterm labor and if the salivary estriol was well below the threshold of the alarm level, then, in fact, that's very reassuring. Many patients are, appropriately, very concerned about having a preterm birth because they know what the consequence of that is. So if it's low, that's very reassuring. On the other hand, if it's higher, above the threshold, that's of concern too. What we do at the University of Colorado is ask those patients to come in to be seen, and we go over them from head to toe. We see if we can find a reason for this premature signal, and the vast majority of folks who actually do."

Ada Popek: "Doctor, how accurate or telling is this test? Will we catch every preterm labor?"

Dr. McGregor: "No. It may be that preterm labor results from other kinds of problems that don't have to do with natural, physiologic mechanisms-trauma, a bleeding episode, or a medical induction for labor-that really won't be determined because those have other causes. But for the normal, everyday pre-term birth, this test is very reliable-over 80%."

Ada Popek: "Now let me ask you one more question - do you tend to get many false-positive results with this test?"

Dr. McGregor: "No, the positives are really positive. That's fascinating; it's nature's own signal. So in fact, when it's positive, that's of concern-it's not like a test that's kind of wishy-washy. This is a test that's actually surging, the hormone is actually surging, so you don't get false-positives. You could get false-negatives, but they're caused by other processes like infection, bleeding, trauma, preeclampsia, or things that we physicians induce patients for."

Ada Popek: "Now do you think by watching the trend or the results of the SalEst test, that that's the most important way to utilize the test or to look for a cut-off value?"

Dr. McGregor: "Ada, the patients themselves, as well as the care providers-doctors and nurses-are actually happier to plot each weekly level so they can see how a pregnancy's going. It's fascinating. We live out in Colorado, and relatives from the east coast who want to come to be there for the birth can actually ask, 'how's the plot going?' Or, they even want to be faxed the results."

Ada Popek: "Thank you very much, Dr. McGregor."

Dr. McGregor: "You bet."

Ada Popek: "We appreciate your help."