The question remained as to who actually wanted such a test, as there is no indication that Modahl, whose appeal against her four-year ban for doping abuse starts on Monday week, is pressing for it.
Tony Ward, spokesman for the British Athletic Federation, said: "Last January our two experts in this case agreed it would be useful, but not essential, if a third test was carried out. That information was passed to the IAAF, and we now understand that the third test is to be carried out."
No details of a forthcoming test have yet been given to Diane Modahl or her legal advisers.
Another puzzling aspect to the announcement is the fact that the IAAF arranged for a third test on the sample to take place at the original testing laboratory in Lisbon on 22 June, but cancelled it two days beforehand.
Modahl, the 1990 Commonwealth champion at 800 metres, is serving a four- year ban after testing positive for testosterone last year. She would be the first athlete to have a sample tested more than twice.
The impetus for such a test appears to be coming solely from within the BAF. "If they request it, then we have nothing against it," the IAAF general secretary Istvan Gyulai said.
In the meantime, the IAAF have told Michael Johnson that the Olympic schedule will not be altered any further to make it easier for him to run both the 200 and 400m in Atlanta.
The IAAF has added 50 minutes between the 200 semi-finals and the 400 final in Atlanta, giving him two hours 35 minutes between races. Johnson said he wanted to finish all four rounds of the 400 before starting the 200.
Kelly Holmes has been frustrated in her wish to double up at 800 and 1500m at this weekend's KP National Championships and trials. She has been told the schedule cannot be altered as programmes have already been printed.