Age in months (AGEMONTH) is reported for patients less than 11 years of age. AGEMONTH is calculated from date of birth (DOB) and the admission date (ADATE) with the following exceptions:

• AGEMONTH is set to the supplied age in months if the age cannot be calculated (ADATE and/or DOB is missing or invalid).
• AGEMONTH is missing (.) if the age cannot be calculated and the reported age in months is missing.
• AGEMONTH is missing (.) if the calculated age in years is out of range (AGE NE 0-124).
• AGEMONTH is invalid (.A) if the age in months cannot be calculated and the supplied age in months is nonnumeric. An invalid calculated AGEMONTH is not replaced by the reported age in months.
• AGEMONTH is set to inconsistent (.C) if AGEMONTH is inconsistent with neonatal diagnoses (EAGE04), or is inconsistent with maternal diagnoses/procedures (EAGE05).

Patient age in months (AGEMONTH) could not be calculated from dates because Connecticut did not report full dates of birth. During HCUP processing, only the reported age in months could be used to assign AGEMONTH.

Beginning in 2004, Florida no longer provides age in days or months because HCUP can calculate these values from ADATE and DOB.

Prior to 2002, age in months (AGEMONTH) was calculated from admission and birth dates. Beginning in 2002, only the reported age in months could be used because dates were not provided.

Prior to 2001, the reported age in months is available only through 2 years of age. AGEMONTH is missing (.) for patients over 2 years old.

Beginning with the 2001 data, Georgia reported age in months through 11 years of age (0-132 months).

Only the calculated age in months could be used to assign AGEMONTH because Missouri did not supply this information.

Patient age in months (AGEMONTH) could not be calculated from dates because Oklahoma did not report date of birth. During HCUP processing, only the reported age in months could be used to assign AGEMONTH.