At-home test checks post-vasectomy fertility
How many of your patients rely on vasectomy for contraception? About 500,000 vasectomies are performed each year in the United States; about one out of six U.S. men over age 35 has been vasectomized, with prevalence increasing with education and income.1,2
Vasectomy represents one of the most cost-effective methods of contraception, along with the copper-T and levonorgestrel (LNG) intrauterine devices (IUDs).1 Recent research calculated to estimate the relative cost-effectiveness of contraceptives in the United States from a payer's perspective found that vasectomy ($713) falls between the copper-T IUD ($647) and the LNG IUD ($930) as the three least expensive birth control methods over time.3
Most physicians require two post-vasectomy sperm tests to determine fertility status. However, research indicates many do not return post-procedure for a semen analysis. Results from one study indicate that 25% of men who had vasectomies at a Cleveland clinic provided no follow-up semen specimens, and only 21% followed the full instructions to provide two consecutive negative semen analyses, while results of another study show 34% of men never returned to a Michigan private urological practice following their sterilization procedures.4,5
Patients now can check their post-vasectomy sterility at home, as the SpermCheck Vasectomy diagnostic test is now poised to enter the commercial market. The device, which gained Food and Drug Administration approval in March 2008, will enable men to test their post-vasectomy fertility status at home rather than requiring them to return to the physician's office or a laboratory. By placing a few drops of the man's semen in the well of the test device, SpermCheck Vasectomy is designed to return accurate results of negative or positive in less than 10 minutes after the semen sample is added to the device. A negative result indicates a sperm concentration is below 300,000 sperm per milliliter of semen, and it is the desired outcome when testing a man who has undergone a vasectomy.
Following vasectomy, men are required to return to the physician, usually for two follow-up visits to monitor their sperm count, notes John Herr, PhD, director of the University of Virginia Center for Research in Contraceptive and Reproductive Health, and the founder of ContraVac, both based in Charlottesville, VA. Many men do not comply, and pregnancy may occur in the post-vasectomy period before sperm has been "cleared" from the system, Herr explains.
"With a SpermCheck test, a man can take the device home after the operation and perform the test at home, or purchase it directly from the company or in a drug store, eliminating the need to return to the doctor's office," says Herr. "Thus, the device is predicted to improve the determination of the exact timing when the man can engage in safe sex after the operation."
In the laboratory, Herr and research associates worked to identify a gene, named ACRV1, that encoded a protein that could serve as a sperm-specific biomarker. The protein, known as sperm protein-10 (SP-10), is soluble and highly expressed, which makes it an ideal target for diagnostic testing, as in the SpermCheck Vasectomy home test. The testing device uses monoclonal antibodies that bind specifically to the SP-10 protein to measure the amount in nanograms of SP-10 protein present, which yields a direct correlation to the number of sperm present.6
SpermCheck Vasectomy is calibrated to give a positive result when the sperm concentration is greater than 250,000/milliliter (ml), which is a level associated with little or no risk of causing pregnancy. This concentration corresponds to one sperm or fewer per standard high-power microscopic field.
In the clinical trial of the device, researchers used SpermCheck to evaluate a cohort of 144 post-vasectomy semen samples. The test achieved an accuracy rate of 96% in identifying whether sperm counts were greater or less than a threshold of 250,000 sperm per ml. Results indicate SpermCheck to be 100% accurate in identifying whether sperm counts were greater or less than 384,000 sperm per ml.7
The test is easy to use, research indicates. In the consumer study of SpermCheck, 109 lay volunteers demonstrated its ease of use. Volunteers obtained the correct or expected test result in every case and achieved a 97% correct response rate on a 20-question survey about the test.7
It is important for patients to understand that failures can occur with vasectomies. Research estimates there is a probability of 11 failures per 1,000 procedures over two years; half of the failures occurred in the first three months after the vasectomy, and no failures occurred after 72 weeks.8
ContraVac is in talks with biotechnology companies who are interested in national distribution of SpermCheck Vasectomy. The company is close to finalizing distribution terms, reports Ed Leary, ContraVac president.
"These companies have their own sales force that call on urologists," he says. "We envision our primary sales channel as our national distributor selling to the urologist, who will sell to the patient following his vasectomy procedure."
Depending on the distribution agreement, Leary estimates retail sales price (direct to consumers) for a two-test kit at $39.99, with provider price estimated at about $29.99. Discounted pricing will be available for volume purchasers, he says. The company is looking at handling consumer orders via telephone, as well as its web site, www.contravac.com.
References
- Haws JM, Morgan GT, Pollack AE, et al. Clinical aspects of vasectomies performed in the United States in 1995. Urology 1998; 52:685-691.
- Department of Health and Human Services. Facts About Vasectomy Safety. Fact sheet. Accessed at: www.nichd.nih.gov.
- Trussell J, Lalla AM, Doan QV, et al. Cost effectiveness of contraceptives in the United States. Contraception 2009; 79:5-14.
- Dhar NB, Bhatt A, Jones JS. Determining the success of vasectomy. BJU Int 2006; 97:773-776.
- Maatman TJ, Aldrin L, Carothers GG. Patient noncompliance after vasectomy.Fertil Steril 1997; 68:552-555.
- Estabrook M. U.Va. Researcher's Sperm-Check Home Test Receives FDA OK. Press release. March 5, 2008. Accessed at www.virginia.edu.
- Klotz KL, Coppola MA, Labrecque M, et al. Clinical and consumer trial performance of a sensitive immunodiagnostic home test that qualitatively detects low concentrations of sperm following vasectomy. J Urol 2008; 180:2,569-2,576.
- Jamieson DJ, Costello C, Trussell J, et al. The risk of pregnancy after vasectomy. Obstet Gynecol 2004; 103:848-850.
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