diff --git a/README.md b/README.md
index 5d83cde..8fc1bab 100644
--- a/README.md
+++ b/README.md
@@ -25,11 +25,29 @@ const cqlfhir = require('cql-exec-fhir');
 // Code setting up the CQL library, executor, etc, and getting the patient data as a bundle
 // ...
 
-const patientSource = cqlfhir.PatientSource.FHIRv102(); // or .FHIRv300() or .FHIRv400()
+const patientSource = cqlfhir.PatientSource.FHIRv401(); // or .FHIRv102() or .FHIRv300() or .FHIRv400()
 patientSource.loadBundles([patient01, patient02]);
 const results = executor.exec(patientSource);
 ```
 
+## (Optional) Trusted Environment with meta.profile
+
+**NOTE**: This feature will only work with `cql-execution` version 2.4.1 or higher.
+
+If desired, the FHIR Data Source can be configured to use the `meta.profile` list on FHIR resources as a source of truth for whether or not that resource should be included when looking through the Bundle of data.
+
+```js
+const cqlfhir = require('cql-exec-fhir');
+
+// Including "requireProfileTagging: true" in an object passed in to the constructor enables the trusted environment
+const patientSource = cqlfhir.PatientSource.FHIRv401({
+  requireProfileTagging: true,
+}); // or .FHIRv102() or .FHIRv300() or .FHIRv400()
+```
+
+As an example, if an ELM Retrieve expression asks for a FHIR Condition Resource with profile `http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition-encounter-diagnosis`, the default behavior of the FHIR Data Source is to find any FHIR Condition resource.
+With the trusted environment enabled however, the FHIR Data Source will _only_ find resources with the string `'http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition-encounter-diagnosis'` included in their `meta.profile` lists.
+
 # Using the FHIRWrapper
 
 If you are passing in individual FHIR resources to the execution engine as parameters, you can use FHIRWrapper
@@ -39,7 +57,7 @@ Example:
 
 ```js
 const cqlfhir = require('cql-exec-fhir');
-const fhirWrapper = cqlfhir.FHIRWrapper.FHIRv102(); // or .FHIRv300() or .FHIRv400() or .FHIRv401()
+const fhirWrapper = cqlfhir.FHIRWrapper.FHIRv401(); // or .FHIRv102() or .FHIRv300() or .FHIRv400()
 
 const conditionRawResource = { "resourceType": "Condition", "id": "f201", "clinicalStatus": "active", ... }
 const conditionFhirObject = fhirWrapper.wrap(conditionResource)
diff --git a/src/fhir.js b/src/fhir.js
index 66fa097..56a68cb 100644
--- a/src/fhir.js
+++ b/src/fhir.js
@@ -50,30 +50,31 @@ class FHIRWrapper {
 }
 
 class PatientSource {
-  constructor(filePathOrXML) {
+  constructor(filePathOrXML, patientSourceOptions = {}) {
     this._index = 0;
     this._bundles = [];
+    this._patientSourceOptions = patientSourceOptions;
     this._modelInfo = load(filePathOrXML);
   }
 
   // Convenience factory method for getting a FHIR 1.0.2 (DSTU2) Patient Source
-  static FHIRv102() {
-    return new PatientSource(FHIRv102XML);
+  static FHIRv102(patientSourceOptions) {
+    return new PatientSource(FHIRv102XML, patientSourceOptions);
   }
 
   // Convenience factory method for getting a FHIR 3.0.0 (STU3) Patient Source
-  static FHIRv300() {
-    return new PatientSource(FHIRv300XML);
+  static FHIRv300(patientSourceOptions) {
+    return new PatientSource(FHIRv300XML, patientSourceOptions);
   }
 
   // Convenience factory method for getting a FHIR 4.0.0 (R4) Patient Source
-  static FHIRv400() {
-    return new PatientSource(FHIRv400XML);
+  static FHIRv400(patientSourceOptions) {
+    return new PatientSource(FHIRv400XML, patientSourceOptions);
   }
 
   // Convenience factory method for getting a FHIR 4.0.1 (R4) Patient Source
-  static FHIRv401() {
-    return new PatientSource(FHIRv401XML);
+  static FHIRv401(patientSourceOptions) {
+    return new PatientSource(FHIRv401XML, patientSourceOptions);
   }
 
   get version() {
@@ -86,7 +87,7 @@ class PatientSource {
 
   currentPatient() {
     if (this._index < this._bundles.length) {
-      return new Patient(this._bundles[this._index], this._modelInfo);
+      return new Patient(this._bundles[this._index], this._modelInfo, this._patientSourceOptions);
     }
   }
 
@@ -290,7 +291,7 @@ class FHIRObject {
 }
 
 class Patient extends FHIRObject {
-  constructor(bundle, modelInfo) {
+  constructor(bundle, modelInfo, patientSourceOptions = {}) {
     const patientClass = modelInfo.patientClassIdentifier
       ? modelInfo.patientClassIdentifier
       : modelInfo.patientClassName;
@@ -298,19 +299,36 @@ class Patient extends FHIRObject {
     const ptEntry = bundle.entry.find(e => e.resource && e.resource.resourceType == resourceType);
     const ptClass = modelInfo.findClass(patientClass);
     super(ptEntry.resource, ptClass, modelInfo);
+    this._patientSourceOptions = patientSourceOptions;
+
     // Define a "private" un-enumerable property to hold the bundle
     Object.defineProperty(this, '_bundle', { value: bundle, enumerable: false });
   }
 
-  findRecord(profile) {
-    const records = this.findRecords(profile);
+  findRecord(profile, retrieveDetails) {
+    const records = this.findRecords(profile, retrieveDetails);
     if (records.length > 0) {
       return records[0];
     }
   }
 
-  findRecords(profile) {
-    const classInfo = this._modelInfo.findClass(profile);
+  findRecords(profile, retrieveDetails) {
+    const { requireProfileTagging } = this._patientSourceOptions;
+
+    // retrieveDetails was introduced in cql-execution v2.4.1. If it is missing from the function call
+    // profile checking will not work,
+    if (requireProfileTagging === true && retrieveDetails == null) {
+      throw new Error(
+        'meta.profile checking is only supported using cql-execution >=2.4.1. Please upgrade or set the "requireProfileTagging" option to false when constructing a PatientSource.'
+      );
+    }
+
+    // Preferring the datatype on retrieveDetails allows the engine to properly identify resources where
+    // the ELM uses a profile from a specific IG (e.g. US Core)
+    const classInfo = this._modelInfo.findClass(
+      retrieveDetails ? retrieveDetails.datatype : profile
+    );
+
     if (classInfo == null) {
       console.error(`Failed to find type info for ${profile}`);
       return [];
@@ -318,11 +336,35 @@ class Patient extends FHIRObject {
     const resourceType = classInfo.name.replace(/^FHIR\./, '');
     const records = this._bundle.entry
       .filter(e => {
-        return e.resource && e.resource.resourceType == resourceType;
+        if (e.resource && e.resource.resourceType == resourceType) {
+          if (
+            requireProfileTagging === true &&
+            profile !== `http://hl7.org/fhir/StructureDefinition/${resourceType}`
+          ) {
+            return (
+              e.resource.meta &&
+              e.resource.meta.profile &&
+              e.resource.meta.profile.includes(profile)
+            );
+          }
+          return true;
+        }
+        return false;
       })
       .map(e => {
         return new FHIRObject(e.resource, classInfo, this._modelInfo);
       });
+
+    // PatientSources have the assumption that bundles loaded in always have a Patient resources.
+    // When "requireProfileTagging" is true, we could encounter a case where the Patient resource is contained in the Bundle
+    // but does not have meta.profile set to match the Retrieve of the Patient.
+    // In this case, we should throw an error, as we want to ensure that the Patient can properly be retrieved before executing the rest of the ELM Retrieves
+    if (requireProfileTagging === true && resourceType === 'Patient' && records.length === 0) {
+      throw new Error(
+        `Patient record with meta.profile matching ${profile} was not found. Please ensure that meta.profile is properly set on the Patient resource, or set the "requireProfileTagging" option to false when constructing a PatientSource.`
+      );
+    }
+
     return records;
   }
 }
diff --git a/test/dstu2_test.js b/test/dstu2_test.js
index 80f2c95..6d2c30d 100644
--- a/test/dstu2_test.js
+++ b/test/dstu2_test.js
@@ -379,6 +379,74 @@ describe('#DSTU2', () => {
   });
 });
 
+describe('#DSTU2 PatientSource meta.profile checking', () => {
+  let patientSource;
+  before(() => {
+    patientSource = cqlfhir.PatientSource.FHIRv102({
+      requireProfileTagging: true
+    });
+  });
+
+  beforeEach(() => {
+    // patientMyron has 1 Condition resource with a meta.profile set to be a Argonaut Condition
+    // patientShawnee does not have an Argonaut profile included in meta.profile on any resources
+    patientSource.loadBundles([patientMyron, patientShawnee]);
+  });
+
+  afterEach(() => patientSource.reset());
+
+  it('should throw error when trying to use meta.profile with no retrieveDetails', () => {
+    const myron = patientSource.currentPatient();
+    expect(() =>
+      myron.findRecords('http://fhir.org/guides/argonaut/StructureDefinition/argo-condition')
+    ).to.throw();
+  });
+
+  it('should not find any resources without a matching meta.profile', () => {
+    const myron = patientSource.currentPatient();
+    const conditions = myron.findRecords('http://example.com/not-a-real-profile', {
+      datatype: '{http://hl7.org/fhir}Condition'
+    });
+    expect(conditions).to.have.length(0);
+  });
+
+  it('should find resources with matching meta.profile', () => {
+    const myron = patientSource.currentPatient();
+    const conditions = myron.findRecords(
+      'http://fhir.org/guides/argonaut/StructureDefinition/argo-condition',
+      {
+        datatype: '{http://hl7.org/fhir}Condition',
+        templateId: 'http://fhir.org/guides/argonaut/StructureDefinition/argo-condition'
+      }
+    );
+
+    expect(conditions).to.have.length(1);
+    expect(conditions.every(c => c.getTypeInfo().name === 'FHIR.Condition')).to.be.true;
+    expect(conditions[0].meta.profile[0].value).equal(
+      'http://fhir.org/guides/argonaut/StructureDefinition/argo-condition'
+    );
+  });
+
+  it('should throw error if no patient resource is found with "requireProfileTagging" enabled', () => {
+    const shawnee = patientSource.nextPatient();
+    expect(() => {
+      shawnee.findRecords('http://fhir.org/guides/argonaut/StructureDefinition/argo-patient', {
+        datatype: '{http://hl7.org/fhir}Patient',
+        templateId: 'http://fhir.org/guides/argonaut/StructureDefinition/argo-patient'
+      });
+    }).to.throw();
+  });
+
+  it('should find FHIR core resources even when they are not tagged with the core URL', () => {
+    const myron = patientSource.currentPatient();
+    const conditions = myron.findRecords('http://hl7.org/fhir/StructureDefinition/Condition', {
+      datatype: '{http://hl7.org/fhir}Condition',
+      templateId: 'http://hl7.org/fhir/StructureDefinition/Condition'
+    });
+    expect(conditions).to.have.length(9);
+  });
+});
+
 function compact(obj) {
   if (Array.isArray(obj)) {
     return obj.map(o => compact(o));
diff --git a/test/fixtures/dstu2/Myron933_Ondricka197_a901d2b4-30a8-41b9-b94a-f44561d8f809.json b/test/fixtures/dstu2/Myron933_Ondricka197_a901d2b4-30a8-41b9-b94a-f44561d8f809.json
index bb6b9e1..cfd5057 100644
--- a/test/fixtures/dstu2/Myron933_Ondricka197_a901d2b4-30a8-41b9-b94a-f44561d8f809.json
+++ b/test/fixtures/dstu2/Myron933_Ondricka197_a901d2b4-30a8-41b9-b94a-f44561d8f809.json
@@ -257,6 +257,9 @@
       "resource": {
         "resourceType": "Condition",
         "id": "3c57b73b-6f28-45e7-9729-b681a1ec4156",
+        "meta": {
+          "profile": ["http://fhir.org/guides/argonaut/StructureDefinition/argo-condition"]
+        },
         "patient": {
           "reference": "urn:uuid:bb5e0a4a-bcb8-448b-ab0a-69f639b7dd88"
         },
@@ -268,7 +271,7 @@
           "coding": [
             {
               "system": "http://snomed.info/sct",
-              "code": "15777000",
+              "code": "714628002",
               "display": "Prediabetes"
             }
           ],
diff --git a/test/fixtures/r4/Luna60_McCullough561_6662f0ca-b617-4e02-8f55-7275e9f49aa0.json b/test/fixtures/r4/Luna60_McCullough561_6662f0ca-b617-4e02-8f55-7275e9f49aa0.json
index c23665d..ed85ba5 100644
--- a/test/fixtures/r4/Luna60_McCullough561_6662f0ca-b617-4e02-8f55-7275e9f49aa0.json
+++ b/test/fixtures/r4/Luna60_McCullough561_6662f0ca-b617-4e02-8f55-7275e9f49aa0.json
@@ -1687,6 +1687,18 @@
       "resource": {
         "resourceType": "Condition",
         "id": "9934bc4f-58af-4ecf-bb70-b7cc31987fc5",
+        "meta": {
+          "profile": ["http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition-encounter-diagnosis"]
+        },
+        "category": {
+          "coding": [
+            {
+              "system": "http://terminology.hl7.org/CodeSystem/condition-category",
+              "code": "encounter-diagnosis",
+              "display": "Encounter Diagnosis"
+            }
+          ]
+        },
         "clinicalStatus": {
           "coding": [
             {
diff --git a/test/fixtures/stu3/Myron933_Ondricka197_a901d2b4-30a8-41b9-b94a-f44561d8f809.json b/test/fixtures/stu3/Myron933_Ondricka197_a901d2b4-30a8-41b9-b94a-f44561d8f809.json
index ab0234a..1b17103 100644
--- a/test/fixtures/stu3/Myron933_Ondricka197_a901d2b4-30a8-41b9-b94a-f44561d8f809.json
+++ b/test/fixtures/stu3/Myron933_Ondricka197_a901d2b4-30a8-41b9-b94a-f44561d8f809.json
@@ -324,7 +324,8 @@
         "id": "6bf97e86-a3da-4b4b-a4e5-a290c1099719",
         "meta": {
           "profile": [
-            "http://standardhealthrecord.org/fhir/StructureDefinition/shr-encounter-EncounterPerformed"
+            "http://standardhealthrecord.org/fhir/StructureDefinition/shr-encounter-EncounterPerformed",
+            "http://hl7.org/fhir/us/core/StructureDefinition/us-core-encounter"
           ]
         },
         "extension": [
diff --git a/test/r401_test.js b/test/r401_test.js
index a7742de..990f885 100644
--- a/test/r401_test.js
+++ b/test/r401_test.js
@@ -375,6 +375,76 @@ describe('#R4 v4.0.1', () => {
   });
 });
 
+describe('#R4 v4.0.1 PatientSource meta.profile checking', () => {
+  let patientSource;
+  before(() => {
+    patientSource = cqlfhir.PatientSource.FHIRv401({
+      requireProfileTagging: true
+    });
+  });
+
+  beforeEach(() => {
+    // patientLuna has 1 Condition resource with a meta.profile set to be a US Core Condition
+    // patientJohnnie does not have meta.profile set on any resources
+    patientSource.loadBundles([patientLuna, patientJohnnie]);
+  });
+
+  afterEach(() => patientSource.reset());
+
+  it('should throw error when trying to use meta.profile with no retrieveDetails', () => {
+    const luna = patientSource.currentPatient();
+    expect(() =>
+      luna.findRecords(
+        'http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition-encounter-diagnosis'
+      )
+    ).to.throw();
+  });
+
+  it('should not find any resources without a matching meta.profile', () => {
+    const luna = patientSource.currentPatient();
+    const conditions = luna.findRecords('http://example.com/not-a-real-profile', {
+      datatype: '{http://hl7.org/fhir}Condition'
+    });
+    expect(conditions).to.have.length(0);
+  });
+
+  it('should find resources with matching meta.profile', () => {
+    const luna = patientSource.currentPatient();
+    const conditions = luna.findRecords(
+      'http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition-encounter-diagnosis',
+      {
+        datatype: '{http://hl7.org/fhir}Condition',
+        templateId:
+          'http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition-encounter-diagnosis'
+      }
+    );
+    expect(conditions).to.have.length(1);
+    expect(conditions.every(c => c.getTypeInfo().name === 'Condition')).to.be.true;
+    expect(conditions[0].meta.profile[0].value).equal(
+      'http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition-encounter-diagnosis'
+    );
+  });
+
+  it('should throw error if no patient resource is found with "requireProfileTagging" enabled', () => {
+    const johnnie = patientSource.nextPatient();
+    expect(() => {
+      johnnie.findRecords('http://hl7.org/fhir/us/core/StructureDefinition/us-core-patient', {
+        datatype: '{http://hl7.org/fhir}Patient',
+        templateId: 'http://hl7.org/fhir/us/core/StructureDefinition/us-core-patient'
+      });
+    }).to.throw();
+  });
+
+  it('should find FHIR core resources even when they are not tagged with the core URL', () => {
+    const luna = patientSource.currentPatient();
+    const conditions = luna.findRecords('http://hl7.org/fhir/StructureDefinition/Condition', {
+      datatype: '{http://hl7.org/fhir}Condition',
+      templateId: 'http://hl7.org/fhir/StructureDefinition/Condition'
+    });
+    expect(conditions).to.have.length(8);
+  });
+});
+
 function compact(obj) {
   if (Array.isArray(obj)) {
     return obj.map(o => compact(o));
diff --git a/test/r4_test.js b/test/r4_test.js
index 88c941c..423826d 100644
--- a/test/r4_test.js
+++ b/test/r4_test.js
@@ -413,6 +413,76 @@ describe('#R4 v4.0.0', () => {
   });
 });
 
+describe('#R4 PatientSource meta.profile checking', () => {
+  let patientSource;
+  before(() => {
+    patientSource = cqlfhir.PatientSource.FHIRv400({
+      requireProfileTagging: true
+    });
+  });
+
+  beforeEach(() => {
+    // patientLuna has 1 Condition resource with a meta.profile set to be a US Core Condition
+    // patientJohnnie does not have meta.profile set on any resources
+    patientSource.loadBundles([patientLuna, patientJohnnie]);
+  });
+
+  afterEach(() => patientSource.reset());
+
+  it('should throw error when trying to use meta.profile with no retrieveDetails', () => {
+    const luna = patientSource.currentPatient();
+    expect(() =>
+      luna.findRecords(
+        'http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition-encounter-diagnosis'
+      )
+    ).to.throw();
+  });
+
+  it('should not find any resources without a matching meta.profile', () => {
+    const luna = patientSource.currentPatient();
+    const conditions = luna.findRecords('http://example.com/not-a-real-profile', {
+      datatype: '{http://hl7.org/fhir}Condition'
+    });
+    expect(conditions).to.have.length(0);
+  });
+
+  it('should find resources with matching meta.profile', () => {
+    const luna = patientSource.currentPatient();
+    const conditions = luna.findRecords(
+      'http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition-encounter-diagnosis',
+      {
+        datatype: '{http://hl7.org/fhir}Condition',
+        templateId:
+          'http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition-encounter-diagnosis'
+      }
+    );
+    expect(conditions).to.have.length(1);
+    expect(conditions.every(c => c.getTypeInfo().name === 'Condition')).to.be.true;
+    expect(conditions[0].meta.profile[0].value).equal(
+      'http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition-encounter-diagnosis'
+    );
+  });
+
+  it('should throw error if no patient resource is found with "requireProfileTagging" enabled', () => {
+    const johnnie = patientSource.nextPatient();
+    expect(() => {
+      johnnie.findRecords('http://hl7.org/fhir/us/core/StructureDefinition/us-core-patient', {
+        datatype: '{http://hl7.org/fhir}Patient',
+        templateId: 'http://hl7.org/fhir/us/core/StructureDefinition/us-core-patient'
+      });
+    }).to.throw();
+  });
+
+  it('should find FHIR core resources even when they are not tagged with the core URL', () => {
+    const luna = patientSource.currentPatient();
+    const conditions = luna.findRecords('http://hl7.org/fhir/StructureDefinition/Condition', {
+      datatype: '{http://hl7.org/fhir}Condition',
+      templateId: 'http://hl7.org/fhir/StructureDefinition/Condition'
+    });
+    expect(conditions).to.have.length(8);
+  });
+});
+
 function compact(obj) {
   if (Array.isArray(obj)) {
     return obj.map(o => compact(o));
diff --git a/test/stu3_test.js b/test/stu3_test.js
index fd63048..52de1b9 100644
--- a/test/stu3_test.js
+++ b/test/stu3_test.js
@@ -397,6 +397,74 @@ describe('#STU3', () => {
   });
 });
 
+describe('#STU3 PatientSource meta.profile checking', () => {
+  let patientSource;
+  before(() => {
+    patientSource = cqlfhir.PatientSource.FHIRv300({
+      requireProfileTagging: true
+    });
+  });
+
+  beforeEach(() => {
+    // patientMyron has 1 Encounter resource with a meta.profile set to be a US Core Encounter
+    // patientShawnee does not have a US Core profile included in meta.profile on any resources
+    patientSource.loadBundles([patientMyron, patientShawnee]);
+  });
+
+  afterEach(() => patientSource.reset());
+
+  it('should throw error when trying to use meta.profile with no retrieveDetails', () => {
+    const myron = patientSource.currentPatient();
+    expect(() =>
+      myron.findRecords('http://hl7.org/fhir/us/core/StructureDefinition/us-core-encounter')
+    ).to.throw();
+  });
+
+  it('should not find any resources without a matching meta.profile', () => {
+    const myron = patientSource.currentPatient();
+    const encounters = myron.findRecords('http://example.com/not-a-real-profile', {
+      datatype: '{http://hl7.org/fhir}Encounter'
+    });
+    expect(encounters).to.have.length(0);
+  });
+
+  it('should find resources with matching meta.profile', () => {
+    const myron = patientSource.currentPatient();
+    const encounters = myron.findRecords(
+      'http://hl7.org/fhir/us/core/StructureDefinition/us-core-encounter',
+      {
+        datatype: '{http://hl7.org/fhir}Encounter',
+        templateId: 'http://hl7.org/fhir/us/core/StructureDefinition/us-core-encounter'
+      }
+    );
+
+    expect(encounters).to.have.length(1);
+    expect(encounters.every(c => c.getTypeInfo().name === 'Encounter')).to.be.true;
+    expect(encounters[0].meta.profile[1].value).equal(
+      'http://hl7.org/fhir/us/core/StructureDefinition/us-core-encounter'
+    );
+  });
+
+  it('should throw error if no patient resource is found with "requireProfileTagging" enabled', () => {
+    const shawnee = patientSource.nextPatient();
+    expect(() => {
+      shawnee.findRecords('http://hl7.org/fhir/us/core/StructureDefinition/us-core-patient', {
+        datatype: '{http://hl7.org/fhir}Patient',
+        templateId: 'http://hl7.org/fhir/us/core/StructureDefinition/us-core-patient'
+      });
+    }).to.throw();
+  });
+
+  it('should find FHIR core resources even when they are not tagged with the core URL', () => {
+    const myron = patientSource.currentPatient();
+    const conditions = myron.findRecords('http://hl7.org/fhir/StructureDefinition/Condition', {
+      datatype: '{http://hl7.org/fhir}Condition',
+      templateId: 'http://hl7.org/fhir/StructureDefinition/Condition'
+    });
+    expect(conditions).to.have.length(9);
+  });
+});
+
 function compact(obj) {
   if (Array.isArray(obj)) {
     return obj.map(o => compact(o));