The test score is the time taken on the test, in minutes. This can also be converted to an estimated VO2max (maximal oxygen uptake) score using the calculator below and the following formulas, where the value "T" is the total time completed (expressed in minutes and fractions of a minute e.g. 9 minutes 15 seconds = 9.25 minutes). As with many exercise test equations, there have been many regression equations developed that may give varying results. If possible, use the one derived from a similar population and which best suits your needs.
VO2max (ml/kg/min) = 14.76 - (1.379 × T) + (0.451 × T²) - (0.012 × T³)
Women: VO2max (ml/kg/min) = 2.94 x T + 3.74
Women: VO2max (ml/kg/min) = 4.38 × T - 3.9
Men: VO2max (ml/kg/min) = 2.94 x T + 7.65
Young Men: VO2max (ml/kg/min) = 3.62 x T + 3.91
ref: ACSM's Health-Related Physical Fitness Assessment Manual