diff --git a/FUNCTIONS.R b/FUNCTIONS.R
index 95318d267b8278f64369f8d6ad755c0b0442dde8..906d6a68efdddf329d90d469455eb77286f9e6ad 100644
--- a/FUNCTIONS.R
+++ b/FUNCTIONS.R
@@ -136,7 +136,7 @@ runRelativeAntibodyUnits = function(fname1, fname2, MFI_CSV, MFI_N_ANTIGENS, TEM
     endcount_row_number <- which(L_full$xPONENT == "Avg Net MFI")
     
     # Load Excel file
-    L <- as.data.frame(read_excel(fname1, skip = median_row_number+1))
+    L <- as.data.frame(read_excel(fname1, skip = median_row_number+1, col_types = "text"))
     
     ## Find all blank rows (i.e. rows that are all NA).
     ## Then keep rows preceding the first blank row.
@@ -165,7 +165,7 @@ runRelativeAntibodyUnits = function(fname1, fname2, MFI_CSV, MFI_N_ANTIGENS, TEM
     # MFI values as numeric
     L[,-which(colnames(L) %in% c("Location","Sample","Total Events","TotalEvents"))] = lapply(L[,-which(colnames(L) %in% c("Location","Sample","Total Events"))], as.numeric)
     
-    C <- as.data.frame(read_excel(fname1, skip = count_row_number+1))
+    C <- as.data.frame(read_excel(fname1, skip = count_row_number+1, col_types = "text"))
     
     ## Find all blank rows (i.e. rows that are all NA).
     ## Then keep rows preceding the first blank row.