The WebMD article states: "Blood samples for these cardiac enzyme tests are usually drawn every 8 to 12 hours for 1 to 2 days after a suspected heart attack, to look for the rise and fall in the enzyme levels."

This is especially important for women during a cardiac event, but alas this recommended protocol is rarely followed for women. Hospital ER staff usually perform blood tests 4-6 hours after the onset of symptoms - appropriate in males whose troponin levels tend to peak within that time frame. Women's troponin levels, however, tend to peak around 18 hours.

As cardiologist Dr. Sharonne Hayes of the Mayo Women's Heart Clinic wrote to WomenHeart: The National Coalition For Women With Heart Disease: "These findings are discouraging and reflect true disparities in care. We have to acknowledge that health care providers’ best efforts are hindered by the lack of good science about women and heart disease."

This is partly why many women in mid-heart attack are being misdiagnosed and sent home from the ER with "normal" test results. I was one of them - despite presenting with textbook symptoms like chest pain, nausea, pain radiating down my left arm - my two troponin tests were "normal" and I was sent home after five five hours in the ER with a misdiagnosis of GERD (acid reflux).

More at http://myheartsisters.org/category/diagnosing-and-misdiagnosing/