diff --git a/NAMESPACE b/NAMESPACE
index d87bf9397..464cced34 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -115,6 +115,7 @@ export(process_tests_ae)
 export(process_tests_alarms_telecare)
 export(process_tests_care_home)
 export(process_tests_cmh)
+export(process_tests_delayed_discharges)
 export(process_tests_district_nursing)
 export(process_tests_episode_file)
 export(process_tests_gp_ooh)
diff --git a/R/process_tests_delayed_discharges.R b/R/process_tests_delayed_discharges.R
new file mode 100644
index 000000000..b540d1f74
--- /dev/null
+++ b/R/process_tests_delayed_discharges.R
@@ -0,0 +1,50 @@
+#' Process Delayed Discharges tests
+#'
+#' @description Takes the processed Delayed Discharges extract and produces
+#' a test comparison with the previous data. This is written to disk as a CSV.
+#'
+#' @param data a [tibble][tibble::tibble-package] of the processed data extract.
+#' @param year the financial year of the extract in the format '1718'.
+#'
+#' @return a [tibble][tibble::tibble-package] containing a test comparison.
+#'
+#' @export
+process_tests_delayed_discharges <- function(data, year) {
+  old_data <- get_existing_data_for_tests(data)
+
+  comparison <- produce_test_comparison(
+    old_data = produce_source_dd_tests(old_data),
+    new_data = produce_source_dd_tests(data)
+  ) %>%
+    write_tests_xlsx(sheet_name = "DD", year)
+
+  return(comparison)
+}
+
+#' Delayed Discharges extract tests
+#'
+#' @description Produce tests for the delayed discharges extract.
+#'
+#' @param data new or old data for testing summary flags
+#' (data is from [get_source_extract_path()])
+#'
+#' @return a dataframe with a count of each flag
+#' from [calculate_measures()]
+#'
+#' @family extract test functions
+#' for creating test flags
+#' @seealso calculate_measures
+produce_source_dd_tests <- function(data) {
+  test_flags <- data %>%
+    dplyr::mutate(
+      n_delay_episodes = 1L,
+      code9_episodes = .data$primary_delay_reason == "9"
+    ) %>%
+    create_hb_test_flags(.data$hbtreatcode) %>%
+    # keep variables for comparison
+    dplyr::select(c("n_delay_episodes":dplyr::last_col())) %>%
+    # use function to sum new test flags
+    calculate_measures(measure = "sum")
+
+  return(test_flags)
+}
diff --git a/_targets.R b/_targets.R
index 0886466a8..f50045aed 100644
--- a/_targets.R
+++ b/_targets.R
@@ -310,12 +310,18 @@ list(
         year
       )
     ),
-    # TODO add tests for the Delayed Discharges extract
     tar_target(source_dd_extract, process_extract_delayed_discharges(
       dd_data,
       year,
       write_to_disk = write_to_disk
     )),
+    tar_target(
+      tests_source_dd_extract,
+      process_tests_delayed_discharges(
+        source_dd_extract,
+        year
+      )
+    ),
     tar_target(source_dn_extract, process_extract_district_nursing(
       dn_data,
       year,
diff --git a/man/process_tests_delayed_discharges.Rd b/man/process_tests_delayed_discharges.Rd
new file mode 100644
index 000000000..68e1b8f17
--- /dev/null
+++ b/man/process_tests_delayed_discharges.Rd
@@ -0,0 +1,20 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/process_tests_delayed_discharges.R
+\name{process_tests_delayed_discharges}
+\alias{process_tests_delayed_discharges}
+\title{Process Delayed Discharges tests}
+\usage{
+process_tests_delayed_discharges(data, year)
+}
+\arguments{
+\item{data}{a \link[tibble:tibble-package]{tibble} of the processed data extract.}
+
+\item{year}{the financial year of the extract in the format '1718'.}
+}
+\value{
+a \link[tibble:tibble-package]{tibble} containing a test comparison.
+}
+\description{
+Takes the processed Delayed Discharges extract and produces
+a test comparison with the previous data. This is written to disk as a CSV.
+}
diff --git a/man/produce_source_dd_tests.Rd b/man/produce_source_dd_tests.Rd
new file mode 100644
index 000000000..2eb9f6455
--- /dev/null
+++ b/man/produce_source_dd_tests.Rd
@@ -0,0 +1,28 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/process_tests_delayed_discharges.R
+\name{produce_source_dd_tests}
+\alias{produce_source_dd_tests}
+\title{Delayed Discharges extract tests}
+\usage{
+produce_source_dd_tests(data)
+}
+\arguments{
+\item{data}{new or old data for testing summary flags
+(data is from \code{\link[=get_source_extract_path]{get_source_extract_path()}})}
+}
+\value{
+a dataframe with a count of each flag
+from \code{\link[=calculate_measures]{calculate_measures()}}
+}
+\description{
+Produce tests for the delayed discharges extract.
+}
+\seealso{
+calculate_measures
+
+Other extract test functions
+for creating test flags: 
+\code{\link{produce_source_pis_tests}()}
+}
+\concept{extract test functions
+for creating test flags}
diff --git a/man/produce_source_pis_tests.Rd b/man/produce_source_pis_tests.Rd
index 070cc789d..487ad2fd7 100644
--- a/man/produce_source_pis_tests.Rd
+++ b/man/produce_source_pis_tests.Rd
@@ -24,6 +24,10 @@ episode date variables.
 }
 \seealso{
 calculate_measures
+
+Other extract test functions
+for creating test flags: 
+\code{\link{produce_source_dd_tests}()}
 }
 \concept{extract test functions
 for creating test flags}