Total peak area | Mean values (SE) | 5 | 6 | 7 | |||

1 | 2 | 3 | 4 | ||||

Control(n = 158) | Total cases(n = 65) | Autism(n = 58) | Asperger syndrome (n = 7) | p Value,control/cases | p Value,all groups | Size of difference detectable | |

A. Complete spectrum* | 1209 (18) | 1229 (28) | 1219 (30) | 1311 (86) | 0.55 | 0.51 | ±7.9% |

B. Truncated spectrum* | 506.8 (8.0) | 518.1 (12.4) | 516.9 (13.2) | 528.6 (37.9) | 0.44 | 0.71 | ±8.2% |

C. Creatinine adjusted complete spectrum† | 2.685 (0.003) | 2.690 (0.005) | 2.691 (0.005) | 2.683 (0.014) | 0.34 | 0.56 | ±0.6% |

D. Creatinine adjusted truncated spectrum† | 2.558 (0.003) | 2.567 (0.005) | 2.569 (0.006) | 2.545 (0.016) | 0.18 | 0.16 | ±0.7% |

E. Creatinine content* | 28.58 (0.62) | 27.7 (0.96) | 27.09 (1.02) | 32.55 (2.93) | 0.44 | 0.16 | ±11.3% |

*Using square root transformed data; †using repeated log transformed data.

A comparison of the creatinine concentration in the urine is also shown. The final column presents the minimum difference between the control and autistic spectrum disorder groups detectable at 8% statistical power given the observed variability, as a percentage of the observed mean of the control group. SE, standard error.