diff --git a/app/Controllers/Opd.php b/app/Controllers/Opd.php
index af14e1d..a70c2a3 100644
--- a/app/Controllers/Opd.php
+++ b/app/Controllers/Opd.php
@@ -2796,20 +2796,24 @@ class Opd extends BaseController
         };
 
         $rxInvestigation = $rxRead($rx, ['investigation', 'Investigations', 'investigations', 'Investigation']);
+        
+        // Build test list independently from textarea content
         $rxInvestigationTestList = '';
-        if ($rxInvestigation === '' && !empty($data['rx_investigations']) && is_array($data['rx_investigations'])) {
-            $parts = [];
+        if (!empty($data['rx_investigations']) && is_array($data['rx_investigations'])) {
             $testNames = [];
             foreach ($data['rx_investigations'] as $inv) {
                 $txt = trim((string) ($inv['investigation_name'] ?? $inv['investigation'] ?? ''));
                 if ($txt !== '') {
-                    $parts[] = $txt;
                     $testNames[] = $txt;
                 }
             }
-            $rxInvestigation = implode(', ', $parts);
             
-            // Build formatted test list for {{Tadvise_test_list}} placeholder
+            // If textarea is empty, also populate it with comma-separated tests
+            if ($rxInvestigation === '' && !empty($testNames)) {
+                $rxInvestigation = implode(', ', $testNames);
+            }
+            
+            // Always build formatted HTML test list for {{Tadvise_test_list}} placeholder
             if (!empty($testNames)) {
                 $rxInvestigationTestList = '<ul style="margin:3px 0 0 16px;padding:0;list-style-type:disc;">';
                 foreach ($testNames as $testName) {