To do this you'll need to add some code, using the translation functionalities provided by Magento.
Lookup the file
frontend\base\default\template\catalog/product/view/attributes.phtml, this is the phtml file you'll need to edit for this. Copy it to your local template directory and edit it.
Go to line
46, there the value is outputted. Replace
<td class="data"><?php echo $_helper->productAttribute($_product, $_data['value'], $_data['code']) ?></td>
<td class="data"><?php echo $this->__('%d attr_' . $_data['code'], (int)$_helper->productAttribute($_product, $_data['value'], $_data['code'])) ?></td>
Let's say your attribute code is
carats, the Magento translate function will now look for the string
%d attr_carats in the translation CSVs. All you need to do now is add this string to the local translation CSV like this
"%d attr_carats","%d Cts" and you will get the right label outputted in the attributes table in the Product detail page.
You can do this for every attribute you want to add a suffix to.