diff --git a/server/src/services/__tests__/consultaHistoryService.test.ts b/server/src/services/__tests__/consultaHistoryService.test.ts
new file mode 100644
index 0000000..ac670ee
--- /dev/null
+++ b/server/src/services/__tests__/consultaHistoryService.test.ts
@@ -0,0 +1,69 @@
+import { ConsultaHistory } from '../../models/ConsultaHistory';
+import { ConsultaHistoryService } from '../consultaHistoryService';
+
+jest.mock('../../models/ConsultaHistory', () => ({
+  ConsultaHistory: {
+    countDocuments: jest.fn(),
+    aggregate: jest.fn()
+  }
+}));
+
+describe('ConsultaHistoryService.getConsultaStats', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('guards daily stats aggregation by converting invalid createdAt values safely', async () => {
+    const tenantId = 'tenant-test';
+    const countDocumentsMock = ConsultaHistory.countDocuments as jest.Mock;
+    const aggregateMock = ConsultaHistory.aggregate as jest.Mock;
+
+    countDocumentsMock
+      .mockResolvedValueOnce(2)
+      .mockResolvedValueOnce(1)
+      .mockResolvedValueOnce(1)
+      .mockResolvedValueOnce(1)
+      .mockResolvedValueOnce(1);
+
+    aggregateMock
+      .mockResolvedValueOnce([{ totalCredits: 1 }])
+      .mockResolvedValueOnce([{ avgTime: 150 }])
+      .mockResolvedValueOnce([{ _id: '2026-01-02', count: 1 }])
+      .mockResolvedValueOnce([{ _id: '/api/rut/lookup', count: 2 }]);
+
+    const stats = await ConsultaHistoryService.getConsultaStats(tenantId);
+
+    expect(stats.totalConsultations).toBe(2);
+    expect(stats.consultationsByDay).toEqual([{ date: '2026-01-02', count: 1 }]);
+    expect(stats.consultationsByEndpoint).toEqual([{ endpoint: '/api/rut/lookup', count: 2 }]);
+
+    expect(aggregateMock).toHaveBeenCalledTimes(4);
+
+    const dailyStatsPipeline = aggregateMock.mock.calls[2][0];
+    expect(dailyStatsPipeline).toEqual(
+      expect.arrayContaining([
+        { $match: { tenantId } },
+        {
+          $addFields: {
+            createdAtDate: {
+              $convert: {
+                input: '$createdAt',
+                to: 'date',
+                onError: null,
+                onNull: null
+              }
+            }
+          }
+        },
+        { $match: { createdAtDate: { $ne: null } } }
+      ])
+    );
+    const groupStage = dailyStatsPipeline.find((stage: any) => stage.$group);
+    expect(groupStage.$group._id).toEqual({
+      $dateToString: {
+        format: '%Y-%m-%d',
+        date: '$createdAtDate'
+      }
+    });
+  });
+});
diff --git a/server/src/services/consultaHistoryService.ts b/server/src/services/consultaHistoryService.ts
index 0d570cd..9caab70 100644
--- a/server/src/services/consultaHistoryService.ts
+++ b/server/src/services/consultaHistoryService.ts
@@ -1,6 +1,5 @@
 import { ConsultaHistory, IConsultaHistory, IConsultaHistoryWithUser } from '../models/ConsultaHistory';
 import { AuthenticatedRequest } from '../types/auth';
-import { Request, Response } from 'express';
 import { EvaluationJob, EvaluationResult } from '../models/evaluation';
 
 export interface ConsultaLogData {
@@ -286,9 +285,22 @@ export class ConsultaHistoryService {
       ]),
       ConsultaHistory.aggregate([
         { $match: query },
+        {
+          $addFields: {
+            createdAtDate: {
+              $convert: {
+                input: '$createdAt',
+                to: 'date',
+                onError: null,
+                onNull: null
+              }
+            }
+          }
+        },
+        { $match: { createdAtDate: { $ne: null } } },
         {
           $group: {
-            _id: { $dateToString: { format: '%Y-%m-%d', date: '$createdAt' } },
+            _id: { $dateToString: { format: '%Y-%m-%d', date: '$createdAtDate' } },
             count: { $sum: 1 }
           }
         },
diff --git a/server/src/setupTests.ts b/server/src/setupTests.ts
index a62596d..3d15779 100644
--- a/server/src/setupTests.ts
+++ b/server/src/setupTests.ts
@@ -4,7 +4,7 @@ import dotenv from 'dotenv';
 import { TextEncoder, TextDecoder } from 'util';
 
 // Polyfills for Node.js environment
-global.TextEncoder = TextEncoder;
+global.TextEncoder = TextEncoder as any;
 global.TextDecoder = TextDecoder as any;
 
 // Load test environment variables
@@ -57,8 +57,13 @@ jest.mock('../services/notificationService', () => ({
 
 // Global test database setup
 let mongoServer: MongoMemoryServer;
+const shouldStartMongoMemoryServer = process.env.SKIP_MONGO_MEMORY_SERVER !== 'true';
 
 beforeAll(async () => {
+  if (!shouldStartMongoMemoryServer) {
+    return;
+  }
+
   // Start in-memory MongoDB instance
   mongoServer = await MongoMemoryServer.create();
   const mongoUri = mongoServer.getUri();
@@ -68,6 +73,10 @@ beforeAll(async () => {
 });
 
 beforeEach(async () => {
+  if (!shouldStartMongoMemoryServer || mongoose.connection.readyState !== 1) {
+    return;
+  }
+
   // Clear all collections before each test
   const collections = mongoose.connection.collections;
   for (const key in collections) {
@@ -77,6 +86,10 @@ beforeEach(async () => {
 });
 
 afterAll(async () => {
+  if (!shouldStartMongoMemoryServer || !mongoServer || mongoose.connection.readyState === 0) {
+    return;
+  }
+
   // Cleanup
   await mongoose.connection.dropDatabase();
   await mongoose.connection.close();
@@ -148,4 +161,4 @@ export const createMockResponse = () => {
   res.cookie = jest.fn().mockReturnValue(res);
   res.clearCookie = jest.fn().mockReturnValue(res);
   return res;
-};
\ No newline at end of file
+};