Figure 3.

Evolution of Q_{I gG} with decreasing Q_{A lb} and at constant ITS. Q_{I gG_basal} (red circles) is arbitrarily fixed as equal to Q _mean and three examples of constant ITS levels are depicted (2, 15, and 30 mg/L). Q_{I gG} decreases as Q_{A lb} decreases. Since the variance of normal Q_{I gG} is skewed for lower Q_{A lb}, the Q_{I gG} values associated with an ITS may progressively reach an abnormal range as long as Q_{A lb} decreases. IgG index increases as Q_{A lb} decreases.