NACB - Scientific Shorts
NACB - Scientific Shorts (formerly NACB Blog)
By David G. Grenache, PhD, DABCC, FACB
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The concept of performing lab tests in the privacy of one’s home is enticing which is one reason why home testing is such a lucrative industry. Arguably, the most popular of these are tests of fertility: ovulation prediction and pregnancy tests. Although less well-known, there are also home tests that can be used to assess male fertility (i.e. sperm counts and motility). However, to my knowledge, there are no literature reports on the effectiveness of the sperm tests and so this post will be restricted to tests of female fertility.

Home lab tests of female fertility are largely restricted to urine tests that are used to predict ovulation and diagnose pregnancy. Ovulation prediction tests rely on the detection of the surge of luteinizing hormone (LH) that occurs 1-2 days prior to ovulation. While these tests do an excellent job at detecting the increased concentration of LH in the urine their ability to actually predict ovulation within 48 hours of testing is not as robust . Unfortunately, nearly all of the studies that have evaluated ovulation prediction tests are more than 15 years old now and current devices have not been well-tested. That said, these types of devices have not changed much over the last several years and a report in the popular press suggested that the devices were insufficiently sensitive for 12% of the population (2). Perhaps most interesting (but not surprising) is that nearly all studies of ovulation prediction tests have been performed on women who were seeking medical assistance for infertility. In this population, the ability of ovulation prediction tests to increase fecundity is not clear. While some studies reported that conception rates were not significantly different from controls, others reported increased rates of conception in women that used the tests. A single study performed on women with normal menstrual cycles reported significantly greater pregnancy rates with a fertility monitor that detected the LH surge and estrone-3-glucoronide, a metabolite of estrogen, in urine. So, while the evidence is cloudy at best, these types of fertility tests are quite popular and will likely enjoy continued use by those who wish to increase their chances of achieving pregnancy.
 
I’m willing to bet that the urine pregnancy test is the most frequently performed test at home. They’ve changed considerably since first introduced to the home market in 1977. Then, the hemagglutination-based tests took ~2 hours to produce a result whereas today, results are available within minutes. All of these tests are designed to detect human chorionic gonadotropin (hCG) in urine when it’s present above a concentration threshold. Most interesting to laboratorians is the fact that home pregnancy tests appear to be more analytically sensitive than those used in health care settings ! This may be a function of sample volume differences. Whereas pregnancy tests used in health care settings often require 0.1-0.2 mL to perform, home test devices often require 10 times that volume. Another interesting fact about urine pregnancy tests is that many can detect variants of hCG other than the biologically intact form of the hormone . This is a double-edged sword. While diverse analytical specificity could potentially improve analytical sensitivity, it has also been implicated as a cause of false-negative results . Perhaps most surprising of all is the lack of evidence showing that the rapid detection of hCG in urine has any impact on patient outcome. Studies have shown that health care providers like having these types of tests available but is that sufficient to justify their use in health care settings if no other improvements in patient care can be demonstrated?
 
Point-of-care reproductive tests are certainly not going to go away due to lack of evidence of effectiveness. Still, there are several unanswered questions that need to be addressed. Who is up for the challenge of answering them?

 

 

 

 

 

 

 

 

 

 

 

 

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About the Author
David G. Grenache, PhD, DABCC, FACB
David G. Grenache, PhD, DABCC, FACB 
 

References

1. NACB. Evidenced-based Practice for Point-of-Care Testing. NACB Practice Guidelines. 2006.

2. When the test really counts. Consumer Reports 2003 February: 45-50.

3. Cervinski MA, Lockwood CM, Ferguson AM, Odem RR, Stenman UH, Alfthan H, et al. Qualitative point-of-care and over-the-counter urine hCG devices differentially detect the hCG variants of early pregnancy. Clin Chim Acta. 2009;406(1-2):81–85.

4. Sigel CS, Grenache DG. Detection of unexpected isoforms of human chorionic gonadotropin by qualitative tests. Clin Chem. 2007;53(5):989–990.

5. Gronowski AM, Cervinski M, Stenman U-H, Woodworth A, Ashby L, Scott MG. False-negative results in point-of-care qualitative human chorionic gonadotropin (hCG) devices due to excess hCGbeta core fragment. Clin Chem. 2009;55(7):1389–1394.

6. Greene, D: What could be simpler than a pregnancy test? NACBLOG