diff --git a/scripts/case_selection/export_bpc_selected_cases.R b/scripts/case_selection/export_bpc_selected_cases.R
index ff6ac28f..faab50dd 100644
--- a/scripts/case_selection/export_bpc_selected_cases.R
+++ b/scripts/case_selection/export_bpc_selected_cases.R
@@ -84,7 +84,7 @@ print("get clinical data")
 sex_mapping <- synTableQuery("SELECT * FROM syn7434222")$asDataFrame()
 race_mapping <- synTableQuery("SELECT * FROM syn7434236")$asDataFrame()
 ethnicity_mapping <- synTableQuery("SELECT * FROM syn7434242")$asDataFrame()
-# sample_type_mapping <- synTableQuery("SELECT * FROM syn7434273")$asDataFrame()
+#sample_type_mapping <- synTableQuery("SELECT * FROM syn7434273")$asDataFrame()
 
 # output setup
 phase_no_space <- sub(" ","_",sub(" ","",phase))
@@ -120,35 +120,23 @@ existing_patients = selected_cases[selected_cases %in% clinical$patient_id]
 samples_per_patient <- clinical$sample_id[clinical$patient_id %in% selected_cases]
 
 print("map data for each instrument")
-# mapping data for each instrument
 # instrument - patient_characteristics
-patient_output <- data.frame("record_id" = existing_patients)
-patient_output$redcap_repeat_instrument <- rep("")
-patient_output$redcap_repeat_instance <- rep("")
-
-patient_output$genie_patient_id <- patient_output$record_id
-patient_output$birth_year <- clinical$birth_year[match(patient_output$genie_patient_id, clinical$patient_id)]
-patient_output$naaccr_ethnicity_code <- clinical$ethnicity[match(patient_output$genie_patient_id, clinical$patient_id)]
-patient_output$naaccr_race_code_primary <- clinical$primary_race[match(patient_output$genie_patient_id, clinical$patient_id)]
-patient_output$naaccr_race_code_secondary <- clinical$secondary_race[match(patient_output$genie_patient_id, clinical$patient_id)]
-patient_output$naaccr_race_code_tertiary <- clinical$tertiary_race[match(patient_output$genie_patient_id, clinical$patient_id)]
-patient_output$naaccr_sex_code <- clinical$sex[match(patient_output$genie_patient_id, clinical$patient_id)]
-
-# mapping to code
-patient_output$naaccr_ethnicity_code <- ethnicity_mapping$CODE[match(patient_output$naaccr_ethnicity_code, ethnicity_mapping$CBIO_LABEL)]
-patient_output$naaccr_race_code_primary <- race_mapping$CODE[match(patient_output$naaccr_race_code_primary, race_mapping$CBIO_LABEL)]
-patient_output$naaccr_race_code_secondary <- race_mapping$CODE[match(patient_output$naaccr_race_code_secondary, race_mapping$CBIO_LABEL)]
-patient_output$naaccr_race_code_tertiary <- race_mapping$CODE[match(patient_output$naaccr_race_code_tertiary, race_mapping$CBIO_LABEL)]
-patient_output$naaccr_sex_code <- sex_mapping$CODE[match(patient_output$naaccr_sex_code,sex_mapping$CBIO_LABEL)]
+patient_output <- remap_patient_characteristics(clinical, existing_patients, ethnicity_mapping, race_mapping, sex_mapping)
+# check missing values
+# get naaccr code columns
+naaccr_col <- grep("naaccr", colnames(patient_output), value = TRUE)
+# error out if NAs or empty strings are detected in naaccr code columns
+check_for_missing_values(patient_output, naaccr_col)
+
 print("recode")
 # recode
 # cannotReleaseHIPAA = NA
 patient_output$birth_year[which(patient_output$birth_year == "cannotReleaseHIPAA")] <- NA
-# -1 Not collected = 9 Unknown
+# -1 Not collected = 9 Unknown whether Spanish or not
 patient_output$naaccr_ethnicity_code[which(patient_output$naaccr_ethnicity_code == -1)] <- 9
-# -1 Not collected = 99 Unknown
+# -1 Not collected = 99 Unknown by patient
 patient_output$naaccr_race_code_primary[which(patient_output$naaccr_race_code_primary == -1)] <- 99
-# -1 Not collected = 88 according to NAACCR
+# -1 Not collected = 88 No further race documented according to NAACCR
 patient_output$naaccr_race_code_secondary[which(patient_output$naaccr_race_code_secondary == -1)] <- 88
 patient_output$naaccr_race_code_tertiary[which(patient_output$naaccr_race_code_tertiary == -1)] <- 88
 
diff --git a/scripts/case_selection/shared_fxns.R b/scripts/case_selection/shared_fxns.R
index 2c1a581b..c70e9d5f 100644
--- a/scripts/case_selection/shared_fxns.R
+++ b/scripts/case_selection/shared_fxns.R
@@ -255,4 +255,59 @@ get_main_genie_clinical_id <- function(release){
     }
   }
   return(NULL)
-}
\ No newline at end of file
+}
+
+#'  Mapping data for patient_characteristics
+#' 
+#' @param clinical A data frame of released clinical data for selected cases
+#' @param existing_patients A data frame of available patient after case selection
+#' @param ethnicity_mapping The NAACCR_ETHNICITY_MAPPING data frame
+#' @param race_mapping The NAACCR_RACE_MAPPING data frame
+#' @param sex_mapping The NAACCR_SEX_MAPPING data frame
+#' @return A data frame with mapped code
+remap_patient_characteristics <- function(clinical, existing_patients, ethnicity_mapping, race_mapping, sex_mapping){
+  
+  patient_df <- data.frame("record_id" = existing_patients)
+  patient_df$redcap_repeat_instrument <- rep("")
+  patient_df$redcap_repeat_instance <- rep("")
+  
+  patient_df$genie_patient_id <- patient_df$record_id
+  patient_df$birth_year <- clinical$birth_year[match(patient_df$genie_patient_id, clinical$patient_id)]
+  patient_df$naaccr_ethnicity_code <- clinical$ethnicity_detailed[match(patient_df$genie_patient_id, clinical$patient_id)]
+  patient_df$naaccr_race_code_primary <- clinical$primary_race_detailed[match(patient_df$genie_patient_id, clinical$patient_id)]
+  patient_df$naaccr_race_code_secondary <- clinical$secondary_race_detailed[match(patient_df$genie_patient_id, clinical$patient_id)]
+  patient_df$naaccr_race_code_tertiary <- clinical$tertiary_race_detailed[match(patient_df$genie_patient_id, clinical$patient_id)]
+  patient_df$naaccr_sex_code <- clinical$sex_detailed[match(patient_df$genie_patient_id, clinical$patient_id)]
+  
+  # mapping to code
+  patient_df$naaccr_ethnicity_code <- ethnicity_mapping$CODE[match(patient_df$naaccr_ethnicity_code, ethnicity_mapping$DESCRIPTION)]
+  patient_df$naaccr_race_code_primary <- race_mapping$CODE[match(patient_df$naaccr_race_code_primary, race_mapping$DESCRIPTION)]
+  patient_df$naaccr_race_code_secondary <- race_mapping$CODE[match(patient_df$naaccr_race_code_secondary, race_mapping$DESCRIPTION)]
+  patient_df$naaccr_race_code_tertiary <- race_mapping$CODE[match(patient_df$naaccr_race_code_tertiary, race_mapping$DESCRIPTION)]
+  patient_df$naaccr_sex_code <- sex_mapping$CODE[match(patient_df$naaccr_sex_code,sex_mapping$DESCRIPTION)]
+
+  return(patient_df)
+}
+
+#' Check for missing values in naaccr columns
+#'
+#' @param data The data frame to check against
+#' @param columns The target columns
+check_for_missing_values <- function(data, columns) {
+  # Check for NA values or empty strings
+  missingness_col <- c()
+  for (col in columns) {
+    if (col %in% c("naaccr_race_code_tertiary", "naaccr_race_code_secondary")) {
+      # filter out CHOP, PROV, JHU centers with known NAs in NAACCR code columns
+      relevant_rows <- data[!grepl("CHOP|PROV|JHU", data$genie_patient_id), ]
+    } else{
+      relevant_rows <- data
+    }
+    if (any(is.na(relevant_rows[[col]]) | relevant_rows[[col]] == "" )){
+      missingness_col <- c(col, missingness_col)
+    }
+    }
+  if (length(missingness_col) > 0) {
+    warning(paste0("Warning: Missing or empty values found in column(s): ", paste(missingness_col,collapse=", ")))
+    }
+}
diff --git a/scripts/case_selection/tests/test_shared_fxns.R b/scripts/case_selection/tests/test_shared_fxns.R
index 60aa7604..fdd7fdb3 100644
--- a/scripts/case_selection/tests/test_shared_fxns.R
+++ b/scripts/case_selection/tests/test_shared_fxns.R
@@ -52,3 +52,90 @@ test_that("get_main_genie_clinical_id returns NULL when data_clinical.txt does n
   result <- get_main_genie_clinical_id(release)
   expect_null(result)
 })
+
+test_that("remap_patient_characteristics works as expected", {
+  
+  # Mock input data
+  clinical <- data.frame(
+    patient_id = c(1, 2, 3),
+    birth_year = c(1980, 1990, 2000),
+    ethnicity_detailed = c("Hispanic", "Non-Hispanic", "Hispanic"),
+    primary_race_detailed = c("White", "Black", "Asian"),
+    secondary_race_detailed = c("Unknown", "White", "Black"),
+    tertiary_race_detailed = c("Asian", "Unknown", "White"),
+    sex_detailed = c("Male", "Female", "Male")
+  )
+  
+  existing_patients <-  c(1, 2, 3)
+  
+  ethnicity_mapping <- data.frame(
+    DESCRIPTION = c("Hispanic", "Non-Hispanic"),
+    CODE = c("1", "2")
+  )
+  
+  race_mapping <- data.frame(
+    DESCRIPTION = c("White", "Black", "Asian", "Unknown"),
+    CODE = c("1", "2", "3", "99")
+  )
+  
+  sex_mapping <- data.frame(
+    DESCRIPTION = c("Male", "Female"),
+    CODE = c("M", "F")
+  )
+  
+  # Expected output
+  expected_output <- data.frame(
+    record_id = c(1, 2, 3),
+    redcap_repeat_instrument = c("", "", ""),
+    redcap_repeat_instance = c("", "", ""),
+    genie_patient_id = c(1, 2, 3),
+    birth_year = c(1980, 1990, 2000),
+    naaccr_ethnicity_code = c("1", "2", "1"),
+    naaccr_race_code_primary = c("1", "2", "3"),
+    naaccr_race_code_secondary = c("99", "1", "2"),
+    naaccr_race_code_tertiary = c("3", "99", "1"),
+    naaccr_sex_code = c("M", "F", "M")
+  )
+  
+  # Run the function
+  result <- remap_patient_characteristics(clinical, existing_patients, ethnicity_mapping, race_mapping, sex_mapping)
+  
+  # Test if the output is as expected
+  expect_equal(result, expected_output)
+})
+
+test_that("check_for_missing_values - no missing or empty values", {
+  data <- data.frame(
+    col1 = c(1, 2, 3),
+    col2 = c("a", "b", "c"),
+    genie_patient_id = c("a", "b", "CHOP123"),
+    naaccr_race_code_tertiary = c("a", "b", "c"),
+    naaccr_race_code_secondary = c("a", "b", "c")
+  )
+  expect_no_warning(check_for_missing_values(data, c("col1", "col2", "naaccr_race_code_tertiary", "naaccr_race_code_secondary")))
+
+})
+
+test_that("check_for_missing_values - missingness values are detected in NAACCR code columns in centers other than CHOP, PROV, JHU", {
+  data <- data.frame(
+    col1 = c(1, NA, ""),
+    col2 = c("a", "b", "c"),
+    genie_patient_id = c("CHOP123", "b", "PROV234"),
+    naaccr_race_code_tertiary = c("a", "", "c"),
+    naaccr_race_code_secondary = c("a", "b", "c")
+  )
+  expect_warning(check_for_missing_values(data, c("col1", "col2", "naaccr_race_code_tertiary", "naaccr_race_code_secondary")), 
+              "Warning: Missing or empty values found in column\\(s\\): naaccr_race_code_tertiary, col1")
+})
+
+test_that("check_for_missing_values - missingness values are detected in NAACCR code columns in CHOP, PROV, JHU centers", {
+  data <- data.frame(
+    col1 = c(1, NA, ""),
+    col2 = c("a", "", "c"),
+    genie_patient_id = c("CHOP123", "b", "PROV234"),
+    naaccr_race_code_tertiary = c("", "b", "c"),
+    naaccr_race_code_secondary = c("a", "b", NA)
+  )
+  expect_warning(check_for_missing_values(data, c("col1", "col2", "naaccr_race_code_tertiary", "naaccr_race_code_secondary")), 
+               "Warning: Missing or empty values found in column\\(s\\): col2, col1")
+})