In response to the public LIGO/Virgo gravitational wave (GW) alert of the on-going osservative run O3, with trigger event name S190421ar at T0 = 2019-04-21 21:38:56 (UT), the AGILE Team performed a quick look follow-up analysis of the AGILE data.
The AGILE satellite at T0 was in the South Atlantic Anomaly (SAA) and scientific telemetry was inhibited, however, exposure of the field was obtained both before and after T0.

Preliminary results and MCAL and GRID upper limits have been published in two GCN CIRCULARS:
GCN #24140: LIGO-Virgo S190421ar: AGILE MCAL observations (A. Ursi et al.)
GCN #24143: LIGO-Virgo S190421ar: AGILE GRID observations (M. Cardillo et al.)