<prompt> Answer this question truthfullyWhat is the formula for determining the delta-delta ratio in the context of a metabolic acidosis, and what does this ratio help to determine?  <response>: <reason> In the context of a metabolic acidosis, the delta-delta ratio to determine the presence of a secondary metabolic disorder is calculated using the formula AG-1224-HCO3. This ratio helps to determine whether there is an additional metabolic disorder present that is contributing to the acid-base disturbance. 