Ectopic pregnancies occur when the foetus implants itself outside of the womb, usually in one of the fallopian tubes. The baby can never be saved, but if the condition is not diagnosed in time it can also be fatal for the mother.
Now, an international team has developed the test which checks for four characteristics or "markers" in the blood which are symptomatic of an ectopic pregnancy.
According to the scientists, the test would enable the life-threatening condition to be diagnosed within a day, instead of the several weeks it takes for tests to come back, allowing doctors to intervene earlier to save the reproductive organs which are often severely damaged by the condition.
Doctors currently use blood screening and ultrasound to detect abnormalities, but these methods are not accurate in the early stages following conception. However, the blood test could be accurate just three weeks into pregnancy, the 'Daily Mail' reported.
It would enable women to have immediate surgery to remove the foetus, reducing the chances of the fallopian tube being damaged, say the scientists, led by the University of Pennsylvania School of Medicine in the US.
Team leader Dr Mary Rausch said thousands of women could benefit and lives could be saved. "Potentially this could be a test that somebody in early pregnancy could use to diagnose ectopic pregnancy.
"If they are definitely diagnosed with an ectopic pregnancy, then they could be immediately treated. Most of the time these days people get to hospital pretty quickly and have emergency surgery, but it is a threat."
In their research, the scientists took blood samples from 100 women who had already had an ectopic pregnancy and compared them with samples from 100 healthy women. They found they were correctly able to diagnose 42 per cent of ectopic pregnancies.
Added an expert, Patrick O' Brien, of Royal College of Obstetricians and Gynaecologists: "This test is potentially useful for making an earlier diagnosis. It will be interesting to see if these promising results are borne out in a larger study."