Talk of semen and sperm is anything but a giggling business for the more than 45 million couples worldwide dealing with infertility—and more than 40 percent of those cases involve male infertility. To help such couples, Harvard medical researchers have developed a smartphone attachment that could enable easy and inexpensive home fertility tests for men.
The new device, which resembles a chunky smartphone charging case or cradle, has a slot for a disposable microchip slide containing the semen sample. That enables men to quickly load up a sample and get back results from a custom smartphone app within five seconds. The low cost and convenience could prove revolutionary for many couples who otherwise must rely on pricey and time-consuming lab tests to get the most accurate fertility test results—an option that is often out of reach for many low-income families in both industrialized and developing countries.
"This can make home fertility testing for men as simple as home pregnancy testing for women," says Hadi Shafiee, an assistant professor in medicine at Brigham and Women's Hospital, Harvard Medical School.
Testing of 350 patient semen samples—including both fresh and cryopreserved samples—showed how the new smartphone device can detect abnormal semen samples with almost 98 percent accuracy. It judges semen based on two of three key indicators used by the World Health Organization: sperm count per milliliter of fluid, or concentration; and how many sperm are moving, known as motility. (The third, unused indicator, how many sperm have normal shapes, is referred to as morphology.) Additional details appear in the 22 March 2017 online issue of the journal Science Translational Medicine.
Home use seems pretty easy. Once a man has, um, downloaded his DNA package into a small cup, he simply dips end of the microchip slide into the cup, and squeezes a small rubber bulb on the slide in order to draw the sperm sample up into the microchip. The contaminated disposable tip of the slide snaps off easily so that the microchip sample can be loaded into the slot on the smartphone attachment.
The smartphone attachment is made from materials costing just $4.45 total. These include: a 3D-printed case with a white LED to provide lighting, two extra lenses to boost the optical power of the smartphone's existing camera, a low-cost battery and some electronics plus wiring. Initial tests used Moto X, Moto G4, and LG G4 handsets, but slight device modifications could probably allow it to accommodate most phones.
The easy-to-use smartphone app relies upon proprietary software algorithms to count individual sperm and detect their movements. The app's analysis of each sample takes less than five seconds and runs entirely on the smartphone hardware, which means it does not need to spend time sending the data to a more powerful laptop computer or to cloud computing resources.
"It was challenging for us from a software perspective to do the whole analysis on the phone and to measure both motility and total sperm count in a very rapid manner," Shafiee says.
The Harvard researchers hope to improve the software so that it can eventually detect abnormal sperm shapes and disregard similar-size cells in the semen sample. Shafiee declined at this time to comment on whether the software relies on popular and powerful machine learning techniques. (His only comment on that subject came during a marathon session of back-to-back phone interviews: "You're the first reporter to talk about that.")
Shafiee emphasized that the new smartphone-based test could fill a "gap" that exists in terms of home fertility tests for men. Products such as FertilMARQ and SpermCheck use a chemical staining approach. Trak, another product approved by the U.S. Food and Drug Administration (FDA), uses a small spinning centrifuge to measure sperm concentration in a microfluidic device. But all these products only measure sperm concentration, whereas the Harvard device can also measure motility.
Perhaps the closest competitor for the Harvard smartphone device is the YO Home Sperm Test developed by Medical Electronic Systems. The $49.95 home testing kit became available for purchase in early 2017 and is marketed as "the first FDA-cleared Smartphone based solution for testing your motile sperm."
But Shafiee seemed skeptical of Medical Electronic Systems' test after looking at the documentation filed with the FDA. He pointed out that the YO test relies on a new measure called "motile sperm concentration" that describes a "normal" cutoff point of 6 million motile sperm per milliliter. By comparison, WHO standards measure normal motility as having greater than 40 percent motile sperm in each semen sample. That leaves open the possibility that the YO test could rate certain samples as "normal" that would be considered abnormal under WHO standards.
"Imagine a sample with 100 million sperm per ml and the motility is 10 percent," Shafiee explains. "Based on clinical practice and WHO guidelines, this is abnormal because it falls below 40 percent on motility—but YO would identify it as healthy."
The YO test's accuracy was also mainly compared with that of another proprietary Medical Electronic Systems lab test that relies upon the same, somewhat questionable "motile sperm concentration" measure. The Harvard team compared its smartphone device's results with the current standard methods used to diagnose male infertility: manual microscope-based testing, and computer-assisted semen analysis (CASA). And last but not least, Shafiee also pointed out that the Harvard team's research has just been published in a peer-reviewed journal.
There may be plenty of market opportunities for the Harvard device in any case. Besides couples dealing with infertility, there are more than 33 million couples with male partners who underwent vasectomy as a form of contraception. Vasectomy procedures in the U.S. number between 175,000 and 550,000 procedures per year. The Harvard smartphone device or similar devices could help such men regularly check their semen samples to make sure that their vasectomy holds up—a follow-up practice that is highly recommended but often ignored because of the inconvenience of current testing methods.
Animal breeders might even benefit from a similar form of smartphone-based testing kit that lets them perform fertility tests for livestock on the spot instead of waiting on time-consuming transfers to equipped labs. But "considering the differences between human semen and animal semen in terms of sperm concentration, motility, and sample volume, the current version of the smartphone-based semen analyzer would need to be augmented for applications in animal breeding," say the Harvard researchers. In other words, we're going to need a bigger sampling device.