diff --git a/apps/accounts/migrations/0005_auto_20200515_0038.py b/apps/accounts/migrations/0005_auto_20200515_0038.py
index 06ad9767e71301cf01e9ff4119c9b385cc340295..744e184138c28947144a469d74d6bf33b5860833 100644
--- a/apps/accounts/migrations/0005_auto_20200515_0038.py
+++ b/apps/accounts/migrations/0005_auto_20200515_0038.py
@@ -14,6 +14,11 @@ class Migration(migrations.Migration):
         migrations.AlterField(
             model_name='account',
             name='phone_number',
-            field=models.CharField(max_length=64, validators=[django.core.validators.RegexValidator(message='Phone number has 9-15 digits, allowed to have + prefix', regex='^\\+?\\d{9,15}$')]),
+            field=models.CharField(
+                max_length=64,
+                validators=[
+                    django.core.validators.RegexValidator(
+                        message='Phone number has 9-15 digits, allowed to have + prefix',
+                        regex='^\\+?\\d{9,15}$')]),
         ),
     ]
diff --git a/apps/cases/filters.py b/apps/cases/filters.py
index 4fc53df483f81487c91741e64419c4e9430a369d..3b1d2c346dd16b84fe182c56489189a281d67c08 100644
--- a/apps/cases/filters.py
+++ b/apps/cases/filters.py
@@ -45,12 +45,14 @@ INVESTIGATION_CASE_FILTERSET_FIELDS = (
     "reference_case__is_referral_needed",
     "reference_case__medical_facility_reference",
     "reference_case__outcome",
+    "reference_case__is_positive",
     "case_relation",
     "medical_symptoms",
     "risk_factors",
     "is_referral_needed",
     "medical_facility_reference",
     "outcome",
+    "is_positive",
     "author__name",
     "created_at",
 )
@@ -67,12 +69,14 @@ INVESTIGATION_CASE_SEARCH_FIELDS = (
     "reference_case__risk_factors",
     "reference_case__medical_facility_reference",
     "reference_case__outcome",
+    "reference_case__is_positive",
     "reference_case__created_at",
     "case_relation",
     "medical_symptoms",
     "risk_factors",
     "medical_facility_reference",
     "outcome",
+    "is_positive",
     "author__name",
 )
 
@@ -90,6 +94,7 @@ INVESTIGATION_CASE_ORDERING_FIELDS = (
     "reference_case__is_referral_needed",
     "reference_case__medical_facility_reference",
     "reference_case__outcome",
+    "reference_case__is_positive",
     "reference_case__created_at",
     "case_relation",
     "medical_symptoms",
@@ -97,6 +102,7 @@ INVESTIGATION_CASE_ORDERING_FIELDS = (
     "is_referral_needed",
     "medical_facility_reference",
     "outcome",
+    "is_positive",
     "author__name",
     "created_at",
 )
@@ -115,6 +121,7 @@ MONITORING_CASE_FILTERSET_FIELDS = (
     "investigation_case__reference_case__is_referral_needed",
     "investigation_case__reference_case__medical_facility_reference",
     "investigation_case__reference_case__outcome",
+    "investigation_case__reference_case__is_positive",
     "is_referred",
     "is_checked",
     "is_medicated",
@@ -138,6 +145,7 @@ MONITORING_CASE_SEARCH_FIELDS = (
     "investigation_case__reference_case__risk_factors",
     "investigation_case__reference_case__medical_facility_reference",
     "investigation_case__reference_case__outcome",
+    "investigation_case__reference_case__is_positive",
     "investigation_case__reference_case__created_at",
     "is_referred",
     "is_checked",
@@ -163,6 +171,7 @@ MONITORING_CASE_ORDERING_FIELDS = (
     "investigation_case__reference_case__is_referral_needed",
     "investigation_case__reference_case__medical_facility_reference",
     "investigation_case__reference_case__outcome",
+    "investigation_case__reference_case__is_positive",
     "investigation_case__reference_case__created_at",
     "is_referred",
     "is_checked",
diff --git a/apps/cases/migrations/0012_auto_20200518_1532.py b/apps/cases/migrations/0012_auto_20200518_1532.py
new file mode 100644
index 0000000000000000000000000000000000000000..2625d81c4c501995bb77ecf67c77ac78586b6936
--- /dev/null
+++ b/apps/cases/migrations/0012_auto_20200518_1532.py
@@ -0,0 +1,23 @@
+# Generated by Django 3.0.1 on 2020-05-18 08:32
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('cases', '0011_monitoring_checking_date'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='investigationcase',
+            name='is_positive',
+            field=models.BooleanField(db_index=True, null=True),
+        ),
+        migrations.AddField(
+            model_name='investigationcasehistory',
+            name='is_positive',
+            field=models.BooleanField(db_index=True, null=True),
+        ),
+    ]
diff --git a/apps/cases/models.py b/apps/cases/models.py
index c045a522616989cfdafbd02a72cfe770de83e3de..804e029762d01ede020abf8c3f6415f1d1a1e10b 100644
--- a/apps/cases/models.py
+++ b/apps/cases/models.py
@@ -79,6 +79,7 @@ class InvestigationCaseHistory(HistoryModel):
     is_referral_needed = models.BooleanField(db_index=True)
     medical_facility_reference = models.CharField(max_length=128, blank=True)
     outcome = models.CharField(max_length=256, blank=True, null=True)
+    is_positive = models.BooleanField(db_index=True, null=True)
     author = models.ForeignKey(
         Account,
         blank=True,
@@ -129,6 +130,7 @@ class InvestigationCase(HistoryEnabledModel):
     is_referral_needed = models.BooleanField(db_index=True)
     medical_facility_reference = models.CharField(max_length=128, blank=True)
     outcome = models.CharField(max_length=256, blank=True, null=True)
+    is_positive = models.BooleanField(db_index=True, null=True)
     author = models.ForeignKey(
         Account,
         blank=True,
diff --git a/apps/cases/serializers.py b/apps/cases/serializers.py
index 038cd46e4924c15e887af46feb6fc66d918af937..610ce15b329bd703af18390004b574d10d7bd5db 100644
--- a/apps/cases/serializers.py
+++ b/apps/cases/serializers.py
@@ -63,6 +63,7 @@ class InvestigationCaseSummarySerializer(serializers.ModelSerializer):
             "is_referral_needed",
             "medical_facility_reference",
             "outcome",
+            "is_positive",
             "author",
             "created_at",
         ]
@@ -88,7 +89,13 @@ class InvestigationCaseSerializer(serializers.ModelSerializer):
 
     def save(self):
         account = self.context.get('request').user.account
-        super(InvestigationCaseSerializer, self).save(author=account)
+
+        outcome = self.validated_data.get('outcome', None)
+        is_positive = None
+        if outcome is not None:
+            is_positive = True if "+" in outcome else False
+
+        super(InvestigationCaseSerializer, self).save(author=account, is_positive=is_positive)
 
     def to_representation(self, instance):
         serializer = InvestigationCaseSummarySerializer(instance)
diff --git a/apps/cases/tests/test_units/test_investigation_cases.py b/apps/cases/tests/test_units/test_investigation_cases.py
index dbf8ff41197a788d7c24886415c4ffaa2367f769..5459f8520aa7702827bd66e25daeac2ff0bf3e5d 100644
--- a/apps/cases/tests/test_units/test_investigation_cases.py
+++ b/apps/cases/tests/test_units/test_investigation_cases.py
@@ -34,6 +34,7 @@ class InvestigationCaseViewTest(APITestCase):
             case_subject=cls.case_subject,
             author=cls.author,
             outcome="BTA+",
+            is_positive=True,
         )
         cls.case = InvestigationCaseFactory(
             author=cls.author,
@@ -209,6 +210,40 @@ class InvestigationCaseViewTest(APITestCase):
             investigation_case_history_current_count, investigation_case_history_prev_count + 1
         )
 
+    def test_edit_investigation_to_positive_success(self):
+        url = self.BASE_URL + str(self.case.id) + "/"
+
+        data = {
+            "case_subject": str(self.case_subject.id),
+            "reference_case": str(self.reference_case.id),
+            "case_relation": self.case.case_relation,
+            "medical_symptoms": self.case.medical_symptoms,
+            "risk_factors": self.case.risk_factors,
+            "is_referral_needed": not self.case.is_referral_needed,
+            "medical_facility_reference": self.case.medical_facility_reference,
+            "outcome": "BTA+",
+        }
+
+        investigation_case_prev_count = InvestigationCase.objects.all().count()
+        positive_case_prev_count = InvestigationCase.objects.filter(is_positive=True).count()
+
+        response = self.client.put(path=url, data=data, format="json",)
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(
+            response.data["is_referral_needed"], not self.case.is_referral_needed
+        )
+
+        investigation_case_current_count = InvestigationCase.objects.all().count()
+        positive_case_current_count = InvestigationCase.objects.filter(is_positive=True).count()
+
+        self.assertEqual(
+            investigation_case_current_count, investigation_case_prev_count
+        )
+
+        self.assertEqual(
+            positive_case_current_count, positive_case_prev_count + 1
+        )
+
     def test_edit_investigation_case_fails_with_incomplete_data(self):
         url = self.BASE_URL + str(self.case.id) + "/"
 
diff --git a/apps/cases/views.py b/apps/cases/views.py
index 541c12d1aee1c6463257cfb7a961b777ff9cf44d..aa5179f07459fd6f99f50a51fe4182d7d9d5eedc 100644
--- a/apps/cases/views.py
+++ b/apps/cases/views.py
@@ -71,7 +71,7 @@ class InvestigationCaseViewSet(viewsets.ModelViewSet):
             query_include_positive = self.request.query_params.get('include_positive', None)
             if query_include_positive is not None:
                 return self.queryset
-            return self.queryset.filter(Q(outcome__isnull=True) | Q(outcome__icontains="-"))
+            return self.queryset.exclude(is_positive=True)
         return self.queryset
 
     def get_serializer_class(self):
@@ -85,8 +85,7 @@ class InvestigationCaseViewSet(viewsets.ModelViewSet):
 
 class InvestigationPositiveCaseAPIView(ListAPIView):
     serializer_class = InvestigationCaseSummarySerializer
-    queryset = InvestigationCase.objects.filter(
-        outcome__isnull=False).exclude(outcome__icontains="-")
+    queryset = InvestigationCase.objects.filter(is_positive=True)
     filter_backends = (DjangoFilterBackend, SearchFilter, OrderingFilter)
     permission_classes = (IsAuthenticated,)
     pagination_class = PageNumberPagination