diff --git a/R/ids.R b/R/ids.R
new file mode 100644
index 0000000..8c9371d
--- /dev/null
+++ b/R/ids.R
@@ -0,0 +1,3 @@
+valid_vfbids <- function(x) {
+  grepl("^VFB_[0-9A-z]{8}$", x, perl = T)
+}
diff --git a/R/utils.R b/R/utils.R
index b8ccf26..0bbb319 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -28,7 +28,3 @@ null2na <- function(x, repl=NA) {
     if(length(y)==0) repl else y
   })
 }
-
-valid_vfbids <- function(x) {
-  grepl("^VFB_[0-9A-z]{8}$", x, perl = T)
-}