diff --git a/code/game/dna/dna_modifier.dm b/code/game/dna/dna_modifier.dm
index 3e19f0bfc1..37b274af96 100644
--- a/code/game/dna/dna_modifier.dm
+++ b/code/game/dna/dna_modifier.dm
@@ -551,7 +551,7 @@
 	if (href_list["selectUIBlock"] && href_list["selectUISubblock"]) // This chunk of code updates selected block / sub-block based on click
 		var/select_block = text2num(href_list["selectUIBlock"])
 		var/select_subblock = text2num(href_list["selectUISubblock"])
-		if ((select_block <= 13) && (select_block >= 1))
+		if ((select_block <= DNA_UI_LENGTH) && (select_block >= 1))
 			src.selected_ui_block = select_block
 		if ((select_subblock <= DNA_BLOCK_SIZE) && (select_subblock >= 1))
 			src.selected_ui_subblock = select_subblock