SpermCheck Fertility, an immunodiagnostic home test that detects normozoospermia and severe oligozoospermia

Abstract

Background: A simple and inexpensive home sperm test could be of considerable value to couples attempting to conceive and to men curious about their fertility potential. A two-strip lateral flow immunochromatographic diagnostic device that allows men to evaluate their sperm count at low cost in the privacy of their own homes is described.

Methods: The ability of SpermCheck Fertility to predict sperm counts obtained using a hemacytometer procedure based on standard World Health Organization methodology was assessed. Test results obtained by lay users were also compared with those obtained by trained laboratory professionals, and the ease of use of the device was evaluated in consumer studies.

Results: A total of 225 semen samples were analyzed in the method comparison, and the performance of SpermCheck Fertility was excellent with over 96% of all samples correctly classified as normozoospermic (> or =2 x 10(7) sperm/ml), oligozoospermic (5 x 10(6)-2 x 10(7) sperm/ml) or severely oligozoospermic (<5 x 10(6) sperm/ml). Consumer studies with 164 lay users demonstrated that SpermCheck Fertility was easy to use. Lay users and laboratory professionals agreed 95% of the time when reading the same test independently. Overall, the correct response rate on a 20-question survey about the test was over 97%.

Conclusions: SpermCheck Fertility is a simple and reliable immunodiagnostic test that can quickly inform men as to whether their sperm count is normal, low or very low. This home test can assist couples in deciding whether to seek comprehensive clinical evaluation of the fertility status of the male partner.

Figure 1

The SpermCheck Fertility lateral-flow immunochromatographic device. The devices are shown before sample has been added. The top half of the plastic housing has been removed in the image on the right to demonstrate the location of reagent components in the device and illustrates the principles underlying the operation of the test. The assay utilizes a pair of monoclonal antibodies that bind to the sperm acrosomal analyte SP-10, which is released from the sperm head into a detergent containing buffer upon semen addition. When diluted semen is applied (1) to the sample well (S), colloidal gold-conjugated monoclonal anti-SP-10 antibodies present on an absorbent pad inside the cassette (2) are rehydrated and bind to the SP-10 antigens. Monoclonal antibodies specific for an independent epitope on the SP-10 protein (3), dried onto the nitrocellulose membranes at the test position (T), capture the gold-antibody–SP-10 complexes as they flow along the membrane by capillarity, resulting in the development of a visible reddish colored line [the color of colloidal gold]. The development of visible lines at the control position (C) of each test strip indicates that the device has functioned properly and fluid has flowed over the test lines (4). See Materials and Methods for additional details, and Fig. 2 for images of devices showing representative test results.

Figure 2

SpermCheck Fertility test devices showing results for normal (left), low (center) and very low (right) sperm concentrations. Presence of the reddish control lines (C) shows that the devices have functioned correctly and the test fluid has completely flowed over the test lines (T), which are calibrated to develop color at 5 × 10⁶ (5M) and 2 × 10⁷ (20M) sperm/ml, respectively. If the control lines do not appear within the 7-min assay period, the test is invalid and the result cannot be interpreted.