diff --git a/Gemfile b/Gemfile
index 0aed6a5fec..70d7174b6d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -43,6 +43,7 @@ gem "kaminari"
 gem "lodash-rails"
 gem "lograge"
 gem "ougai"
+gem "oj"
 gem "parallel", require: false
 gem "passenger"
 gem "pg", ">= 0.18", "< 2.0"
diff --git a/Gemfile.lock b/Gemfile.lock
index 569073c1bf..17c7a222a5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -608,6 +608,7 @@ DEPENDENCIES
   memery
   memory_profiler
   mock_redis
+  oj
   ougai
   parallel
   parallel_tests
diff --git a/app/controllers/api/v3/blood_sugars_controller.rb b/app/controllers/api/v3/blood_sugars_controller.rb
index ba4ab65acc..c484e7c0ae 100644
--- a/app/controllers/api/v3/blood_sugars_controller.rb
+++ b/app/controllers/api/v3/blood_sugars_controller.rb
@@ -12,7 +12,7 @@ def sync_to_user
 
   private
 
-  def region_records
+  def model_sync_scope
     super.for_v3
   end
 
diff --git a/app/controllers/api/v3/facilities_controller.rb b/app/controllers/api/v3/facilities_controller.rb
index 23f284ab8b..5925eba59d 100644
--- a/app/controllers/api/v3/facilities_controller.rb
+++ b/app/controllers/api/v3/facilities_controller.rb
@@ -16,7 +16,7 @@ def current_facility_records
   end
 
   def other_facility_records
-    Statsd.instance.time("other_facility_records.Facility") do
+    time(__method__) do
       Facility
         .with_discarded
         .updated_on_server_since(other_facilities_processed_since, limit)
@@ -45,7 +45,7 @@ def force_resync?
   end
 
   def records_to_sync
-    Statsd.instance.time("records_to_sync.Facility") do
+    time(__method__) do
       other_facility_records
         .with_block_region_id
         .includes(:facility_group)
diff --git a/app/controllers/api/v3/patients_controller.rb b/app/controllers/api/v3/patients_controller.rb
index 323c31427f..e3678deaf0 100644
--- a/app/controllers/api/v3/patients_controller.rb
+++ b/app/controllers/api/v3/patients_controller.rb
@@ -13,25 +13,25 @@ def request_metadata
     {request_user_id: current_user.id, request_facility_id: current_facility.id}
   end
 
-  def region_records
-    super.includes(:address, :phone_numbers, :business_identifiers)
-  end
-
   def current_facility_records
-    Statsd.instance.time("current_facility_records.Patient") do
-      region_records
-        .where(registration_facility: current_facility)
-        .updated_on_server_since(current_facility_processed_since, limit)
+    time(__method__) do
+      @current_facility_records ||=
+        current_facility
+          .prioritized_patients
+          .for_sync
+          .updated_on_server_since(current_facility_processed_since, limit)
     end
   end
 
   def other_facility_records
-    Statsd.instance.time("other_facility_records.Patient") do
-      other_facilities_limit = limit - current_facility_records.count
-
-      region_records
-        .where.not(registration_facility: current_facility)
-        .updated_on_server_since(other_facilities_processed_since, other_facilities_limit)
+    time(__method__) do
+      other_facilities_limit = limit - current_facility_records.size
+      @other_facility_records ||=
+        current_sync_region
+          .syncable_patients
+          .where.not(registration_facility: current_facility)
+          .for_sync
+          .updated_on_server_since(other_facilities_processed_since, other_facilities_limit)
     end
   end
 
diff --git a/app/controllers/api/v3/protocols_controller.rb b/app/controllers/api/v3/protocols_controller.rb
index 327c1bed76..d89be32d30 100644
--- a/app/controllers/api/v3/protocols_controller.rb
+++ b/app/controllers/api/v3/protocols_controller.rb
@@ -16,7 +16,7 @@ def current_facility_records
   end
 
   def other_facility_records
-    Statsd.instance.time("other_facility_records.Protocol") do
+    time(__method__) do
       Protocol
         .with_discarded
         .updated_on_server_since(other_facilities_processed_since, limit)
diff --git a/app/controllers/api/v3/sync_controller.rb b/app/controllers/api/v3/sync_controller.rb
index d5f7ad05dd..7094d97914 100644
--- a/app/controllers/api/v3/sync_controller.rb
+++ b/app/controllers/api/v3/sync_controller.rb
@@ -15,12 +15,11 @@ def __sync_to_user__(response_key)
 
     AuditLog.create_logs_async(current_user, records, "fetch", Time.current) unless disable_audit_logs?
     log_block_level_sync_metrics(response_key)
-
     render(
-      json: {
+      json: Oj.dump({
         response_key => records.map { |record| transform_to_response(record) },
         "process_token" => encode_process_token(response_process_token)
-      },
+      }, mode: :compat),
       status: :ok
     )
   end
diff --git a/app/controllers/api_controller.rb b/app/controllers/api_controller.rb
index ac605730c0..ac4760e1d7 100644
--- a/app/controllers/api_controller.rb
+++ b/app/controllers/api_controller.rb
@@ -68,16 +68,16 @@ def requested_sync_region_id
   end
 
   def validate_facility
-    return head :bad_request unless current_facility.present?
+    head :bad_request unless current_facility.present?
   end
 
   def validate_current_facility_belongs_to_users_facility_group
-    return head :unauthorized unless current_user.present? &&
+    head :unauthorized unless current_user.present? &&
       current_facility_group.facilities.where(id: current_facility.id).present?
   end
 
   def current_user_present?
-    return head :unauthorized unless current_user.present?
+    head :unauthorized unless current_user.present?
   end
 
   def validate_sync_approval_status_allowed
diff --git a/app/controllers/concerns/api/v3/sync_to_user.rb b/app/controllers/concerns/api/v3/sync_to_user.rb
index 0d3819b899..c9cbcb410b 100644
--- a/app/controllers/concerns/api/v3/sync_to_user.rb
+++ b/app/controllers/concerns/api/v3/sync_to_user.rb
@@ -2,46 +2,48 @@ module Api::V3::SyncToUser
   extend ActiveSupport::Concern
 
   included do
-    def region_records
-      model.syncable_to_region(current_sync_region)
-    end
-
     def current_facility_records
-      Statsd.instance.time("current_facility_records.#{model.name}") do
-        region_records
-          .where(patient: prioritized_patients)
-          .updated_on_server_since(current_facility_processed_since, limit)
+      time(__method__) do
+        @current_facility_records ||=
+          model_sync_scope
+            .where(patient: current_facility.prioritized_patients.select(:id))
+            .updated_on_server_since(current_facility_processed_since, limit)
       end
     end
 
+    # this is performance-critical code, be careful while refactoring it
     def other_facility_records
-      Statsd.instance.time("other_facility_records.#{model.name}") do
-        other_facilities_limit = limit - current_facility_records.count
-
-        region_records
-          .where.not(patient: prioritized_patients)
-          .updated_on_server_since(other_facilities_processed_since, other_facilities_limit)
+      time(__method__) do
+        other_facilities_limit = limit - current_facility_records.size
+        @other_facility_records ||=
+          model_sync_scope
+            .where("patient_id = ANY (array(?))",
+              current_sync_region
+                .syncable_patients
+                .where.not(registration_facility: current_facility)
+                .select(:id))
+            .updated_on_server_since(other_facilities_processed_since, other_facilities_limit)
       end
     end
 
     private
 
+    def model_sync_scope
+      model.for_sync
+    end
+
     def model
       controller_name.classify.constantize
     end
 
     def records_to_sync
-      Statsd.instance.time("records_to_sync.#{model.name}") do
+      time(__method__) do
         current_facility_records + other_facility_records
       end
     end
 
-    def prioritized_patients
-      current_facility.registered_patients.with_discarded
-    end
-
     def processed_until(records)
-      records.last.updated_at.strftime(APIController::TIME_WITHOUT_TIMEZONE_FORMAT) if records.present?
+      records.last.updated_at.strftime(APIController::TIME_WITHOUT_TIMEZONE_FORMAT) if records.any?
     end
 
     def response_process_token
@@ -90,5 +92,13 @@ def sync_region_modified?
       return if process_token[:sync_region_id].blank?
       process_token[:sync_region_id] != requested_sync_region_id
     end
+
+    def time(method_name, &block)
+      raise ArgumentError, "You must supply a block" unless block
+
+      Statsd.instance.time("#{method_name}.#{model.name}") do
+        yield(block)
+      end
+    end
   end
 end
diff --git a/app/models/appointment.rb b/app/models/appointment.rb
index 509d69c0b1..7f280edb84 100644
--- a/app/models/appointment.rb
+++ b/app/models/appointment.rb
@@ -40,9 +40,7 @@ class Appointment < ApplicationRecord
   validates :device_created_at, presence: true
   validates :device_updated_at, presence: true
 
-  scope :syncable_to_region, ->(region) {
-    with_discarded.where(patient: Patient.syncable_to_region(region))
-  }
+  scope :for_sync, -> { with_discarded }
 
   def self.all_overdue
     where(status: "scheduled")
diff --git a/app/models/blood_pressure.rb b/app/models/blood_pressure.rb
index 813ff47bd9..d21fb49c34 100644
--- a/app/models/blood_pressure.rb
+++ b/app/models/blood_pressure.rb
@@ -32,9 +32,7 @@ class BloodPressure < ApplicationRecord
       .where(arel_table[:diastolic].lt(THRESHOLDS[:hypertensive][:diastolic]))
   }
 
-  scope :syncable_to_region, ->(region) {
-    with_discarded.where(patient: Patient.syncable_to_region(region))
-  }
+  scope :for_sync, -> { with_discarded }
 
   def critical?
     systolic >= THRESHOLDS[:critical][:systolic] || diastolic >= THRESHOLDS[:critical][:diastolic]
diff --git a/app/models/blood_sugar.rb b/app/models/blood_sugar.rb
index 1a524b75cf..a2cb03d6bc 100644
--- a/app/models/blood_sugar.rb
+++ b/app/models/blood_sugar.rb
@@ -30,10 +30,7 @@ class BloodSugar < ApplicationRecord
   V3_TYPES = %i[random post_prandial fasting].freeze
 
   scope :for_v3, -> { where(blood_sugar_type: V3_TYPES) }
-
-  scope :syncable_to_region, ->(region) {
-    with_discarded.where(patient: Patient.syncable_to_region(region))
-  }
+  scope :for_sync, -> { with_discarded }
 
   THRESHOLDS = {
     high: {random: 300,
diff --git a/app/models/encounter.rb b/app/models/encounter.rb
index be4b1af979..26a0ac2dd3 100644
--- a/app/models/encounter.rb
+++ b/app/models/encounter.rb
@@ -9,9 +9,7 @@ class Encounter < ApplicationRecord
   has_many :blood_pressures, through: :observations, source: :observable, source_type: "BloodPressure"
   has_many :blood_sugars, through: :observations, source: :observable, source_type: "BloodSugar"
 
-  scope :syncable_to_region, ->(region) {
-    with_discarded.where(patient: Patient.syncable_to_region(region))
-  }
+  scope :for_sync, -> { with_discarded }
 
   def self.generate_id(facility_id, patient_id, encountered_on)
     UUIDTools::UUID
diff --git a/app/models/facility.rb b/app/models/facility.rb
index 17cb57c15a..49e26e2d60 100644
--- a/app/models/facility.rb
+++ b/app/models/facility.rb
@@ -215,6 +215,10 @@ def valid_block
     end
   end
 
+  def prioritized_patients
+    registered_patients.with_discarded
+  end
+
   def self.localized_facility_size(facility_size)
     return unless facility_size
     I18n.t("activerecord.facility.facility_size.#{facility_size}", default: facility_size.capitalize)
diff --git a/app/models/medical_history.rb b/app/models/medical_history.rb
index 265b99f25a..4b8567d99c 100644
--- a/app/models/medical_history.rb
+++ b/app/models/medical_history.rb
@@ -29,9 +29,7 @@ class MedicalHistory < ApplicationRecord
   enum hypertension: MEDICAL_HISTORY_ANSWERS, _prefix: true
   enum diagnosed_with_hypertension: MEDICAL_HISTORY_ANSWERS, _prefix: true
 
-  scope :syncable_to_region, ->(region) {
-    with_discarded.where(patient: Patient.syncable_to_region(region))
-  }
+  scope :for_sync, -> { with_discarded }
 
   def indicates_hypertension_risk?
     prior_heart_attack_boolean || prior_stroke_boolean
diff --git a/app/models/patient.rb b/app/models/patient.rb
index 4c171e9960..d54ac0da04 100644
--- a/app/models/patient.rb
+++ b/app/models/patient.rb
@@ -56,7 +56,8 @@ class Patient < ApplicationRecord
 
   attribute :call_result, :string
 
-  scope :syncable_to_region, ->(region) { region.syncable_patients }
+  scope :with_nested_sync_resources, -> { includes(:address, :phone_numbers, :business_identifiers) }
+  scope :for_sync, -> { with_discarded.with_nested_sync_resources }
   scope :search_by_address, ->(term) { joins(:address).merge(Address.search_by_street_or_village(term)) }
   scope :with_diabetes, -> { joins(:medical_history).merge(MedicalHistory.diabetes_yes).distinct }
   scope :with_hypertension, -> { joins(:medical_history).merge(MedicalHistory.hypertension_yes).distinct }
diff --git a/app/models/prescription_drug.rb b/app/models/prescription_drug.rb
index 6d970a93a3..05b047e8f1 100644
--- a/app/models/prescription_drug.rb
+++ b/app/models/prescription_drug.rb
@@ -21,9 +21,7 @@ class PrescriptionDrug < ApplicationRecord
   validates :is_protocol_drug, inclusion: {in: [true, false]}
   validates :is_deleted, inclusion: {in: [true, false]}
 
-  scope :syncable_to_region, ->(region) {
-    with_discarded.where(patient: Patient.syncable_to_region(region))
-  }
+  scope :for_sync, -> { with_discarded }
 
   def self.prescribed_as_of(date)
     where("device_created_at <= ?", date.end_of_day)
diff --git a/app/models/region.rb b/app/models/region.rb
index d1f9d5ac96..070e58c0b1 100644
--- a/app/models/region.rb
+++ b/app/models/region.rb
@@ -100,10 +100,10 @@ def syncable_patients
     case region_type
       when "block"
         registered_patients.with_discarded
-          .union(assigned_patients.with_discarded)
+          .or(assigned_patients.with_discarded)
           .union(appointed_patients.with_discarded)
       else
-        registered_patients
+        registered_patients.with_discarded
     end
   end
 
diff --git a/app/transformers/api/v3/facility_transformer.rb b/app/transformers/api/v3/facility_transformer.rb
index 3bc9f67b74..860f549785 100644
--- a/app/transformers/api/v3/facility_transformer.rb
+++ b/app/transformers/api/v3/facility_transformer.rb
@@ -7,7 +7,9 @@ def to_response(facility)
           "enable_teleconsultation",
           "teleconsultation_phone_number",
           "teleconsultation_isd_code",
-          "teleconsultation_phone_numbers")
+          "teleconsultation_phone_numbers",
+          "organization_name",
+          "facility_group_name")
         .merge(config: {enable_diabetes_management: facility.enable_diabetes_management,
                         enable_teleconsultation: facility.enable_teleconsultation},
                protocol_id: facility.protocol.try(:id))
diff --git a/app/transformers/api/v3/patient_transformer.rb b/app/transformers/api/v3/patient_transformer.rb
index e1a559d0ff..07e41b801a 100644
--- a/app/transformers/api/v3/patient_transformer.rb
+++ b/app/transformers/api/v3/patient_transformer.rb
@@ -59,10 +59,10 @@ def from_nested_request(payload_attributes)
 
     def to_nested_response(patient)
       Api::V3::Transformer.to_response(patient)
-        .except("address_id")
-        .except("registration_user_id")
-        .except("test_data")
-        .except("deleted_by_user_id")
+        .except("address_id",
+          "registration_user_id",
+          "test_data",
+          "deleted_by_user_id")
         .merge(
           "address" => Api::V3::Transformer.to_response(patient.address),
           "phone_numbers" => patient.phone_numbers.map do |phone_number|
diff --git a/app/transformers/api/v3/transformer.rb b/app/transformers/api/v3/transformer.rb
index 0e4c1db30c..256816fc80 100644
--- a/app/transformers/api/v3/transformer.rb
+++ b/app/transformers/api/v3/transformer.rb
@@ -1,31 +1,33 @@
 class Api::V3::Transformer
   class << self
-    def from_request(attributes_of_payload)
-      rename_attributes(attributes_of_payload, key_mapping)
+    def from_request(payload_attributes)
+      rename_attributes(payload_attributes, from_request_key_mapping)
     end
 
     def to_response(model)
-      rename_attributes(model.attributes, inverted_key_mapping).as_json
+      rename_attributes(model.attributes, to_response_key_mapping).as_json
     end
 
     def rename_attributes(attributes, mapping)
-      mapping = mapping.with_indifferent_access
-      attributes
-        .to_hash
-        .except(*mapping.values)
-        .transform_keys! { |key| mapping[key] || key }
-        .with_indifferent_access
+      replace_keys(attributes.to_hash, mapping).with_indifferent_access
     end
 
-    def key_mapping
+    def replace_keys(hsh, mapping)
+      mapping.each do |k, v|
+        hsh[v] = hsh.delete(k)
+      end
+      hsh
+    end
+
+    def from_request_key_mapping
       {
         "created_at" => "device_created_at",
         "updated_at" => "device_updated_at"
       }
     end
 
-    def inverted_key_mapping
-      key_mapping.invert
+    def to_response_key_mapping
+      from_request_key_mapping.invert
     end
   end
 end
diff --git a/spec/controllers/api/v3/appointments_controller_spec.rb b/spec/controllers/api/v3/appointments_controller_spec.rb
index e5104e77c7..e83879e6af 100644
--- a/spec/controllers/api/v3/appointments_controller_spec.rb
+++ b/spec/controllers/api/v3/appointments_controller_spec.rb
@@ -338,6 +338,8 @@ def create_record_list(n, options = {})
         expect(response_1_records.count).to eq 4
         expect(response_1_records.map(&:facility).to_set).to eq Set[request_facility]
 
+        reset_controller
+
         # GET request 2
         get :sync_to_user, params: {limit: 4, process_token: response_1_body["process_token"]}
         response_2_body = JSON(response.body)
diff --git a/spec/controllers/api/v3/blood_pressures_controller_spec.rb b/spec/controllers/api/v3/blood_pressures_controller_spec.rb
index a7c09223de..6152fe312e 100644
--- a/spec/controllers/api/v3/blood_pressures_controller_spec.rb
+++ b/spec/controllers/api/v3/blood_pressures_controller_spec.rb
@@ -304,6 +304,8 @@ def create_record_list(n, options = {})
         expect(records.count).to eq 4
         expect(records.map(&:facility).to_set).to eq Set[request_facility]
 
+        reset_controller
+
         # GET request 2
         get :sync_to_user, params: {limit: 4, process_token: response_1_body["process_token"]}
         response_2_body = JSON(response.body)
diff --git a/spec/controllers/api/v3/blood_sugars_controller_spec.rb b/spec/controllers/api/v3/blood_sugars_controller_spec.rb
index bf52b90e9f..9e7af97d29 100644
--- a/spec/controllers/api/v3/blood_sugars_controller_spec.rb
+++ b/spec/controllers/api/v3/blood_sugars_controller_spec.rb
@@ -283,6 +283,8 @@ def create_record_list(n, options = {})
         expect(records.count).to eq 4
         expect(records.map(&:facility).to_set).to eq Set[request_facility]
 
+        reset_controller
+
         # GET request 2
         get :sync_to_user, params: {limit: 4, process_token: response_1_body["process_token"]}
         response_2_body = JSON(response.body)
diff --git a/spec/controllers/api/v3/encounters_controller_spec.rb b/spec/controllers/api/v3/encounters_controller_spec.rb
index b0c012d5ed..d48253981d 100644
--- a/spec/controllers/api/v3/encounters_controller_spec.rb
+++ b/spec/controllers/api/v3/encounters_controller_spec.rb
@@ -156,6 +156,8 @@ def create_record_list(n, options = {})
         expect(records.count).to eq 4
         expect(records.map(&:facility).to_set).to eq Set[request_facility]
 
+        reset_controller
+
         # GET request 2
         get :sync_to_user, params: {limit: 4, process_token: response_1_body["process_token"]}
         response_2_body = JSON(response.body)
diff --git a/spec/controllers/api/v3/medical_histories_controller_spec.rb b/spec/controllers/api/v3/medical_histories_controller_spec.rb
index fa798941f3..263a4f3825 100644
--- a/spec/controllers/api/v3/medical_histories_controller_spec.rb
+++ b/spec/controllers/api/v3/medical_histories_controller_spec.rb
@@ -61,6 +61,8 @@ def create_record_list(n, options = {})
         expect(response_1_records.count).to eq 4
         expect(response_1_records.map(&:patient).to_set).to eq Set[patient_in_request_facility]
 
+        reset_controller
+
         # GET request 2
         get :sync_to_user, params: {limit: 4, process_token: response_1_body["process_token"]}
         response_2_body = JSON(response.body)
diff --git a/spec/controllers/api/v3/patients_controller_spec.rb b/spec/controllers/api/v3/patients_controller_spec.rb
index 3ce84d44c0..8b8f07a3e9 100644
--- a/spec/controllers/api/v3/patients_controller_spec.rb
+++ b/spec/controllers/api/v3/patients_controller_spec.rb
@@ -357,6 +357,8 @@ def create_record_list(n, options = {})
         expect(records.count).to eq 4
         expect(records.map(&:registration_facility).to_set).to eq Set[request_facility]
 
+        reset_controller
+
         # GET request 2
         get :sync_to_user, params: {limit: 4, process_token: response_1_body["process_token"]}
         response_2_body = JSON(response.body)
diff --git a/spec/controllers/api/v3/prescription_drugs_controller_spec.rb b/spec/controllers/api/v3/prescription_drugs_controller_spec.rb
index 91ff95622b..31dbfb8ea2 100644
--- a/spec/controllers/api/v3/prescription_drugs_controller_spec.rb
+++ b/spec/controllers/api/v3/prescription_drugs_controller_spec.rb
@@ -98,6 +98,8 @@ def create_record_list(n, options = {})
         expect(records.count).to eq 4
         expect(records.map(&:facility).to_set).to eq Set[request_facility]
 
+        reset_controller
+
         # GET request 2
         get :sync_to_user, params: {limit: 4, process_token: response_1_body["process_token"]}
         response_2_body = JSON(response.body)
diff --git a/spec/controllers/api/v4/blood_sugars_controller_spec.rb b/spec/controllers/api/v4/blood_sugars_controller_spec.rb
index d1cc0841ed..d0a1652ccf 100644
--- a/spec/controllers/api/v4/blood_sugars_controller_spec.rb
+++ b/spec/controllers/api/v4/blood_sugars_controller_spec.rb
@@ -270,6 +270,8 @@ def create_record_list(n, options = {})
         expect(records.count).to eq 4
         expect(records.map(&:facility).to_set).to eq Set[request_facility]
 
+        reset_controller
+
         # GET request 2
         get :sync_to_user, params: {limit: 4, process_token: response_1_body["process_token"]}
         response_2_body = JSON(response.body)
diff --git a/spec/controllers/shared_examples/shared_spec_for_sync_controller.rb b/spec/controllers/shared_examples/shared_spec_for_sync_controller.rb
index f68ef134fb..37e6c539bd 100644
--- a/spec/controllers/shared_examples/shared_spec_for_sync_controller.rb
+++ b/spec/controllers/shared_examples/shared_spec_for_sync_controller.rb
@@ -250,6 +250,8 @@ def discard_patient(record)
 
         response_1 = JSON(response.body)
 
+        reset_controller
+
         get :sync_to_user, params: {
           process_token: response_1["process_token"],
           limit: 8
@@ -509,6 +511,8 @@ def discard_patient(record)
           request.env["HTTP_X_SYNC_REGION_ID"] = requested_sync_region_id
           process_token = make_process_token(response_process_token.merge(sync_region_id: process_token_sync_region_id))
 
+          reset_controller
+
           get :sync_to_user, params: {process_token: process_token}
 
           response_record_ids = JSON(response.body)[response_key].map { |r| r["id"] }
diff --git a/spec/models/appointment_spec.rb b/spec/models/appointment_spec.rb
index 5d53c235e5..683a3009a2 100644
--- a/spec/models/appointment_spec.rb
+++ b/spec/models/appointment_spec.rb
@@ -105,28 +105,11 @@
       end
     end
 
-    describe ".syncable_to_region" do
-      it "returns all patients registered in the region" do
-        facility_group = create(:facility_group)
-        facility = create(:facility, facility_group: facility_group)
-        patient = create(:patient)
-        other_patient = create(:patient)
-
-        allow(Patient).to receive(:syncable_to_region).with(facility_group).and_return([patient])
-
-        appointments = [
-          create(:appointment, patient: patient, facility: facility),
-          create(:appointment, patient: patient, facility: facility).tap(&:discard),
-          create(:appointment, patient: patient)
-        ]
-
-        _other_appointments = [
-          create(:appointment, patient: other_patient, facility: facility),
-          create(:appointment, patient: other_patient, facility: facility).tap(&:discard),
-          create(:appointment, patient: other_patient)
-        ]
-
-        expect(Appointment.syncable_to_region(facility_group)).to contain_exactly(*appointments)
+    describe ".for_sync" do
+      it "includes discarded appointments" do
+        discarded_appointment = create(:appointment, deleted_at: Time.now)
+
+        expect(described_class.for_sync).to include(discarded_appointment)
       end
     end
   end
diff --git a/spec/models/blood_pressure_spec.rb b/spec/models/blood_pressure_spec.rb
index cad1851a8e..9677b40f51 100644
--- a/spec/models/blood_pressure_spec.rb
+++ b/spec/models/blood_pressure_spec.rb
@@ -40,28 +40,11 @@
       end
     end
 
-    describe ".syncable_to_region" do
-      it "returns all patients registered in the region" do
-        facility_group = create(:facility_group)
-        facility = create(:facility, facility_group: facility_group)
-        patient = create(:patient)
-        other_patient = create(:patient)
-
-        allow(Patient).to receive(:syncable_to_region).with(facility_group).and_return([patient])
-
-        blood_pressures = [
-          create(:blood_pressure, patient: patient, facility: facility),
-          create(:blood_pressure, patient: patient, facility: facility).tap(&:discard),
-          create(:blood_pressure, patient: patient)
-        ]
-
-        _other_blood_pressures = [
-          create(:blood_pressure, patient: other_patient, facility: facility),
-          create(:blood_pressure, patient: other_patient, facility: facility).tap(&:discard),
-          create(:blood_pressure, patient: other_patient)
-        ]
-
-        expect(BloodPressure.syncable_to_region(facility_group)).to contain_exactly(*blood_pressures)
+    describe ".for_sync" do
+      it "includes discarded blood pressures" do
+        discarded_bp = create(:blood_pressure, deleted_at: Time.now)
+
+        expect(described_class.for_sync).to include(discarded_bp)
       end
     end
   end
diff --git a/spec/models/blood_sugar_spec.rb b/spec/models/blood_sugar_spec.rb
index 84cee1aa7e..439e45d09f 100644
--- a/spec/models/blood_sugar_spec.rb
+++ b/spec/models/blood_sugar_spec.rb
@@ -37,7 +37,7 @@
     end
   end
 
-  describe "scopes" do
+  describe "Scopes" do
     let!(:fasting) { create(:blood_sugar, blood_sugar_type: :fasting) }
     let!(:random) { create(:blood_sugar, blood_sugar_type: :random) }
     let!(:post_prandial) { create(:blood_sugar, blood_sugar_type: :post_prandial) }
@@ -50,28 +50,11 @@
       end
     end
 
-    describe ".syncable_to_region" do
-      it "returns all patients registered in the region" do
-        facility_group = create(:facility_group)
-        facility = create(:facility, facility_group: facility_group)
-        patient = create(:patient)
-        other_patient = create(:patient)
+    describe ".for_sync" do
+      it "includes discarded blood sugars" do
+        discarded_blood_sugar = create(:blood_sugar, deleted_at: Time.now)
 
-        allow(Patient).to receive(:syncable_to_region).with(facility_group).and_return([patient])
-
-        blood_sugars = [
-          create(:blood_sugar, patient: patient, facility: facility),
-          create(:blood_sugar, patient: patient, facility: facility).tap(&:discard),
-          create(:blood_sugar, patient: patient)
-        ]
-
-        _other_blood_sugars = [
-          create(:blood_sugar, patient: other_patient, facility: facility),
-          create(:blood_sugar, patient: other_patient, facility: facility).tap(&:discard),
-          create(:blood_sugar, patient: other_patient)
-        ]
-
-        expect(BloodSugar.syncable_to_region(facility_group)).to contain_exactly(*blood_sugars)
+        expect(described_class.for_sync).to include(discarded_blood_sugar)
       end
     end
   end
diff --git a/spec/models/encounter_spec.rb b/spec/models/encounter_spec.rb
index ca4a9b0f62..1517b68d5f 100644
--- a/spec/models/encounter_spec.rb
+++ b/spec/models/encounter_spec.rb
@@ -34,28 +34,11 @@
   end
 
   describe "Scopes" do
-    describe ".syncable_to_region" do
-      it "returns all patients registered in the region" do
-        facility_group = create(:facility_group)
-        facility = create(:facility, facility_group: facility_group)
-        patient = create(:patient)
-        other_patient = create(:patient)
-
-        allow(Patient).to receive(:syncable_to_region).with(facility_group).and_return([patient])
-
-        encounters = [
-          create(:encounter, patient: patient, facility: facility),
-          create(:encounter, patient: patient, facility: facility).tap(&:discard),
-          create(:encounter, patient: patient)
-        ]
-
-        _other_encounters = [
-          create(:encounter, patient: other_patient, facility: facility),
-          create(:encounter, patient: other_patient, facility: facility).tap(&:discard),
-          create(:encounter, patient: other_patient)
-        ]
-
-        expect(Encounter.syncable_to_region(facility_group)).to contain_exactly(*encounters)
+    describe ".for_sync" do
+      it "includes discarded encounters" do
+        discarded_encounter = create(:encounter, deleted_at: Time.now)
+
+        expect(described_class.for_sync).to include(discarded_encounter)
       end
     end
   end
diff --git a/spec/models/medical_history_spec.rb b/spec/models/medical_history_spec.rb
index d1b9cafe19..0c18937243 100644
--- a/spec/models/medical_history_spec.rb
+++ b/spec/models/medical_history_spec.rb
@@ -11,26 +11,11 @@
   end
 
   describe "Scopes" do
-    describe ".syncable_to_region" do
-      it "returns all patients registered in the region" do
-        facility_group = create(:facility_group)
-        patient = create(:patient)
-        other_patient = create(:patient)
+    describe ".for_sync" do
+      it "includes discarded medical histories" do
+        discarded_medical_history = create(:medical_history, deleted_at: Time.now)
 
-        allow(Patient).to receive(:syncable_to_region).with(facility_group).and_return([patient])
-
-        MedicalHistory.destroy_all
-        medical_histories = [
-          create(:medical_history, patient: patient),
-          create(:medical_history, patient: patient).tap(&:discard)
-        ]
-
-        _other_medical_histories = [
-          create(:medical_history, patient: other_patient),
-          create(:medical_history, patient: other_patient).tap(&:discard)
-        ]
-
-        expect(MedicalHistory.syncable_to_region(facility_group)).to contain_exactly(*medical_histories)
+        expect(described_class.for_sync).to include(discarded_medical_history)
       end
     end
   end
diff --git a/spec/models/patient_spec.rb b/spec/models/patient_spec.rb
index 51ba76dadd..c42c6c6e9e 100644
--- a/spec/models/patient_spec.rb
+++ b/spec/models/patient_spec.rb
@@ -321,27 +321,19 @@
       end
     end
 
-    describe ".syncable_to_region" do
-      it "returns all patients registered in the region" do
-        facility_group = create(:facility_group)
-        other_facility_group = create(:facility_group)
-
-        facility = create(:facility, facility_group: facility_group)
-        other_facility = create(:facility, facility_group: other_facility_group)
-
-        patients = [
-          create(:patient, registration_facility: facility),
-          create(:patient, registration_facility: facility).tap(&:discard),
-          create(:patient, registration_facility: facility, assigned_facility: other_facility)
-        ]
+    describe ".for_sync" do
+      it "includes discarded patients" do
+        discarded_patient = create(:patient, deleted_at: Time.now)
 
-        _other_patients = [
-          create(:patient, registration_facility: other_facility),
-          create(:patient, registration_facility: other_facility).tap(&:discard),
-          create(:patient, registration_facility: other_facility, assigned_facility: facility)
-        ]
+        expect(described_class.for_sync).to include(discarded_patient)
+      end
+
+      it "includes nested sync resources" do
+        _discarded_patient = create(:patient, deleted_at: Time.now)
 
-        expect(Patient.syncable_to_region(facility_group)).to contain_exactly(*patients)
+        expect(described_class.for_sync.first.association(:address).loaded?).to eq true
+        expect(described_class.for_sync.first.association(:phone_numbers).loaded?).to eq true
+        expect(described_class.for_sync.first.association(:business_identifiers).loaded?).to eq true
       end
     end
   end
diff --git a/spec/models/prescription_drug_spec.rb b/spec/models/prescription_drug_spec.rb
index cbfa37c568..4e8ec54a29 100644
--- a/spec/models/prescription_drug_spec.rb
+++ b/spec/models/prescription_drug_spec.rb
@@ -11,37 +11,20 @@
     it { should belong_to(:teleconsultation).optional }
   end
 
-  describe "Behavior" do
-    it_behaves_like "a record that is deletable"
-  end
-
   describe "Scopes" do
-    describe ".syncable_to_region" do
-      it "returns all patients registered in the region" do
-        facility_group = create(:facility_group)
-        facility = create(:facility, facility_group: facility_group)
-        patient = create(:patient)
-        other_patient = create(:patient)
-
-        allow(Patient).to receive(:syncable_to_region).with(facility_group).and_return([patient])
-
-        prescription_drugs = [
-          create(:prescription_drug, patient: patient, facility: facility),
-          create(:prescription_drug, patient: patient, facility: facility).tap(&:discard),
-          create(:prescription_drug, patient: patient)
-        ]
-
-        _other_prescription_drugs = [
-          create(:prescription_drug, patient: other_patient, facility: facility),
-          create(:prescription_drug, patient: other_patient, facility: facility).tap(&:discard),
-          create(:prescription_drug, patient: other_patient)
-        ]
-
-        expect(PrescriptionDrug.syncable_to_region(facility_group)).to contain_exactly(*prescription_drugs)
+    describe ".for_sync" do
+      it "includes discarded prescription drugs" do
+        discarded_prescription_drug = create(:prescription_drug, deleted_at: Time.now)
+
+        expect(described_class.for_sync).to include(discarded_prescription_drug)
       end
     end
   end
 
+  describe "Behavior" do
+    it_behaves_like "a record that is deletable"
+  end
+
   describe ".prescribed_as_of" do
     def remove_drug(prescription_drug, time)
       prescription_drug.update(is_deleted: true, device_updated_at: time)
diff --git a/spec/utils.rb b/spec/utils.rb
index 30d484bf13..a53d486c02 100644
--- a/spec/utils.rb
+++ b/spec/utils.rb
@@ -20,7 +20,12 @@ def to_json_and_back
 
   def with_payload_keys
     Api::V3::Transformer.rename_attributes(
-      self, Api::V3::Transformer.inverted_key_mapping
+      self, Api::V3::Transformer.to_response_key_mapping
     )
   end
 end
+
+def reset_controller
+  controller.instance_variable_set(:@current_facility_records, nil)
+  controller.instance_variable_set(:@other_facility_records, nil)
+end