diff --git a/tests/host_tools/fcmetrics.py b/tests/host_tools/fcmetrics.py
index e33e89089dc..47661d5b27d 100644
--- a/tests/host_tools/fcmetrics.py
+++ b/tests/host_tools/fcmetrics.py
@@ -472,6 +472,7 @@ def flatten_dict(node, prefix: str):
         # See also https://github.com/stefano-garzarella/iperf-vsock/issues/4
         "fc_metrics.vsock.rx_read_fails",
         "fc_metrics.vsock.tx_write_fails",
+        "fc_metrics.vsock.tx_flush_fails",
     ]
 
     failure_metrics = {