A hardware compensation using a reference buffer can be used.
When the REFCTRL.REFCOMP bit is set, the offset of the reference buffer is sensed during the ADC sampling phase. This offset will be then cancelled during the conversion phase. This feature allows to decrease the overall gain error of the ADC.
There is also a digital gain correction (refer to Offset and gain correction chapter) but contrary to that digital gain correction, the hardware compensation won’t introduce any latency.