diff --git a/testing/endtoend/evaluators/metrics.go b/testing/endtoend/evaluators/metrics.go
index 5bb5b57f4e..cdfd38284d 100644
--- a/testing/endtoend/evaluators/metrics.go
+++ b/testing/endtoend/evaluators/metrics.go
@@ -119,8 +119,8 @@ func metricsTest(_ *types.EvaluationContext, conns ...*grpc.ClientConn) error {
 		timeSlot := slots.CurrentSlot(genesisResp.GenesisTime.AsTime())
 		// Allow 1 slot tolerance due to race between calculating current slot
 		// and fetching chain head - a slot boundary may occur between these calls.
-		slotDiff := int64(timeSlot) - int64(chainHead.HeadSlot)
-		if slotDiff < 0 || slotDiff > 1 {
+		// Check: chainHead.HeadSlot <= timeSlot <= chainHead.HeadSlot + 1
+		if uint64(chainHead.HeadSlot) > uint64(timeSlot) || uint64(timeSlot) > uint64(chainHead.HeadSlot)+1 {
 			return fmt.Errorf("expected metrics slot to equal chain head slot, expected %d, received %d", timeSlot, chainHead.HeadSlot)
 		}