In 'Encounter with 2 Times Serum Creatinine Increase', HighCreatinineTest.result.value must be equivalent to "HighestSerumCreatinine"(EncounterWithHighCreatinine). Similarly, LowCreatinineTest.result.value must be equivalent to "LowestSerumCreatinine"(EncounterWithHighCreatinine).

This is problematic when the 'highest' or 'lowest' Creatinine values are after 30 days. SerumCreatinineSequenceByQuantity draws from the entire HospitalizationWithObservation.

When the 'highest' creatinine lab result is after 30 days, these two criterion can never be met. 
and HighCreatinineTest.result.value = "HighestSerumCreatinine"(EncounterWithHighCreatinine)
and HighCreatinineTestTime during Interval[start of HospitalWithObservation + 48 hours, start of HospitalWithObservation + 30 days]
This is similarly problematic for 'Encounter with 1.5 Times Serum Creatinine Increase' with the additional complexity of a rolling 7 day window between the low and high creatinine labs. 

We recommend that Measure Authors revisit the intention of Stage 2 or greater AKI. If it is still desired to impose a 30-day "at-risk" window, we would recommend one of the following:

1. Limit the initial population to patients with a total length of stay under 30 days.
2. Adjust the SerumCreatinineSequence functions and Encounter with 1.5/2.0x Increase statements to sort values within a particular timeframe rather than the entire hospitalization.