If we want to check on a currently identified EL’s proficiency level during the school year, can we use the screener?

The screener is not designed for this purpose. You should either use the WIDA MODEL, which must be purchased from WIDA, or use a locally developed assessment. Keep in mind that formative information that ESL teachers can gather during ongoing interaction with students is very valuable when considering a student’s current ability and level of need. The WIDA proficiency level descriptors, rubrics, and ELD standards can be used to help in this type of analysis.