It is this unreliability that Healthy.io is attempting to deal with. The firm is, for instance, working with doctors in Israel on a system that lets pregnant women at risk of pre-eclampsia (dangerously high blood pressure, which is signalled by protein in the urine) use dip.io to monitor themselves at home. In Britain, meanwhile, the National Health Service (NHS) is starting to employ a version of the app to monitor those suffering from multiple sclerosis whose bladders are affected by the disease. Members of this group, which is around 60,000-strong, are at particular risk of urinary-tract infections. About 5,000 of them develop severe infections every year. At the moment, when someone in this position spots early symptoms he must go to a clinic to be tested. Home-testing, followed by a prescription posted to those who need it, should obviate that need, speed up treatment and also save the NHS around £10m ($12m) a year.

A third dipstick test the app may soon be applied to is chronic kidney disease. In America alone some 26m people have this condition, which is often associated with diabetes and high blood pressure in a phenomenon known as metabolic syndrome. Patients in the late stages of kidney disease need costly dialysis. But if the illness is detected early, by screening the urine of those at risk to check for protein, sufferers can be given drugs that lower their blood pressure and thus slow the disease’s progress.