An Indian and a team of researchers from Harvard Medical School, Boston have developed a smartphone-based semen analyser that will go a long way in identifying the cause of infertility in men — low sperm concentration and motility —with nearly 98% accuracy. The portable, easy to use, automated device can be used by untrained individuals, is highly inexpensive, and provides results in about five seconds.
The device measures sperm concentration and motility based on unwashed, unprocessed semen samples. The accuracy of the device was similar to computer-assisted, lab-based analysis even when performed by untrained users. Male infertility affects over 30 million (12%) of men in the world. The stigma against male infertility prevents many men from getting tested; the new device may help many men to undertake semen analysis at home and in low-resource settings. The results were published on March 22 in the journal Science Translational Medicine.
The smartphone-based platform made by Manoj Kumar Kanakasabapathy, the first author of the paper, has an optical attachment for image magnification and a disposable microfluidic device for loading the semen sample. A disposable microchip with a capillary tip and a rubber bulb is used for simple, power-free semen sample handling. The software has a user-friendly interface that guides the user through each step of testing. The results can be stored on the phone for monitoring over time.
Fifty-six cryopreserved semen samples (with semen count of about 100,000 sperm per ml) were first used to evaluate the device. Though the difference between manual and smartphone-based semen analysis increased as sperm concentration increased, the accuracy was over 98%. The device was evaluated for sensitivity, specificity and accuracy by testing 164 semen samples collected from patients. The device was unable to measure samples that had over 100 million sperm per ml, but was able to accurately detect abnormal semen samples — sperm count less than the WHO threshold of 15 million sperm per ml.
The sensitivity, specificity and accuracy of the device to detect abnormal samples based on semen count alone were 91%, 97% and 96% respectively. In the case of motility, the sensitivity, specificity and accuracy of the device were 99%, 87% and 98% respectively. The sensitivity, specificity and accuracy for both sperm concentration and motility were 99%, 89% and 98% respectively.
The “current version” uses the smartphone camera for sample imaging and different smartphones can be used with minor modifications to the optical arrangement. Three different smartphones (Moto X, Moto G4, and LG G4) were used by the researchers and got the same results. The team also evaluated how well untrained users performed the test using the device.
The device has certain limitations: accuracy suffers when samples contain higher-than-average number of nonsperm cells such as white cells. The algorithm counts sperm based on sperm-head measurement and so cannot differentiate between sperm and other larger cells. It is possible to address this by using more image-intensive image analysis but that would increase the processing time. The device also cannot evaluate sperm morphology.
Besides being used for infertility testing, the device can be used by men for home-based monitoring after undergoing vasectomy. As per guidelines, sperm count should be less than 100,000 sperm per ml between eight and 16 weeks after the vasectomy procedure. Earlier studies have shown that compliance for postvasectomy follow-up semen analysis is “extremely poor”. The device finds application in animal breeding as well.