diff --git a/src/ca/CAref.html b/src/ca/CAref.html
index 7f5881d5f..fb0279f6d 100644
--- a/src/ca/CAref.html
+++ b/src/ca/CAref.html
@@ -739,7 +739,10 @@ implemet this feature.</em></p>
 
 <p>Channel Access Client Library regression test.</p>
 
-<p>Test failure is indicated if the program stops prior to printing "test
+<p>The PV used with the test must be naytive type DBR_DOUBLE or DBR_FLOAT,
+and modified only by acctst while the test is running. Therefore,
+periodically scanned hardware attached analog input records do not work well.
+Test failure is indicated if the program stops prior to printing "test
 complete". If unspecified the progress logging level is zero, and no messages
 are printed while the test is progressing. If unspecified, the channel
 duplication count is 20000. If unspecified, the test repetition count is once