Gross Drug Cost Below Part D Out-of-Pocket Threshold (GDCB)
This variable is the portion of the gross drug cost for the prescription drug fill that was not covered by Part D's catastrophic coverage.
Under Part D, a beneficiary qualifies for catastrophic coverage when his/her true out-of-pocket (TrOOP) costs reach a specific dollar threshold (for example, the threshold was $4,550 in 2010). For prescriptions that were filled when a beneficiary was below the out-of-pocket threshold (OOPT), this field will contain a positive dollar value. For prescriptions above the OOPT, this field will contain a zero dollar amount. If a prescription crosses the threshold, then the portion of the gross drug cost that is below the threshold will appear in this field.
See the GDC_ABV_OOPT_AMT variable for the portion of the gross drug cost that was covered by Part D's catastrophic coverage.
Some additional information on this variable: