diff --git a/src/diagnostics.lua b/src/diagnostics.lua
index a1b82cf..d5cfd36 100644
--- a/src/diagnostics.lua
+++ b/src/diagnostics.lua
@@ -138,12 +138,20 @@ function M.validate_diagnostics(content, workspace_types, root_dir)
       return prefix == "T" or prefix == "D" or prefix == "S"
     end
 
+    -- Check if hash is part of a base-specific number literal like 16#FFFF, 2#1010
+    local function is_number_literal_at(line, match_start)
+      if not line or not match_start then return false end
+      if match_start <= 1 then return false end
+      local before = line:sub(match_start - 1, match_start - 1)
+      return before:match("%d") ~= nil
+    end
+
     if not in_var_section then
       local hash_vars = {}
       for var in line:gmatch("#[%w_]+") do
         local var_name = var:sub(2)
         local match_start = line:find(var, 1, true)
-        if not is_iec_literal_at(line, match_start) then
+        if not is_iec_literal_at(line, match_start) and not is_number_literal_at(line, match_start) then
           hash_vars[var_name] = true
         end
       end