diff --git a/src/controllers/reference_range.ts b/src/controllers/reference_range.ts
index aed5f1a..7fdad7e 100644
--- a/src/controllers/reference_range.ts
+++ b/src/controllers/reference_range.ts
@@ -114,8 +114,8 @@ export class ReferenceRangeController {
 			referenceRange.value_min = param.value_min;
 			referenceRange.value_max = param.value_max;
 			referenceRange.status = param.status;
-			referenceRange.created_by = req.auth.data.name;
-			referenceRange.updated_by = req.auth.data.name;
+			referenceRange.created_by = req.auth?.data.name;
+			referenceRange.updated_by = req.auth?.data.name;
 			await queryRunner.manager.save(referenceRange);
 
 			await queryRunner.commitTransaction();
@@ -191,7 +191,7 @@ export class ReferenceRangeController {
 			referenceRange.value_min = param.value_min;
 			referenceRange.value_max = param.value_max;
 			referenceRange.status = param.status;
-			referenceRange.updated_by = req.auth.data.name;
+			referenceRange.updated_by = req.auth?.data.name;
 			await queryRunner.manager.save(referenceRange);
 
 			await queryRunner.commitTransaction();
@@ -228,7 +228,7 @@ export class ReferenceRangeController {
 
 				if (!referenceRange) throw { message: "Reference Range " + Language.lang.failed_not_found };
 
-				referenceRange.deleted_by = req.auth.data.name;
+				referenceRange.deleted_by = req.auth?.data.name;
 				referenceRange.deleted_at = moment().toDate();
 				await OrmHelper.DB.manager.save(referenceRange);
 				affected = 1;
diff --git a/src/model/reference_range.ts b/src/model/reference_range.ts
index c2fb1fe..f35eb46 100644
--- a/src/model/reference_range.ts
+++ b/src/model/reference_range.ts
@@ -4,20 +4,19 @@ import CommonHelper from "../helpers/common";
 import { OrmHelper } from "../helpers/orm";
 
 export class ReferenceRangeModel {
-	static async list(filter = {}): Promise<SelectQueryBuilder<any>> {
+	static async list(filter: Record<string, any> = {}): Promise<SelectQueryBuilder<any>> {
 		const repo = OrmHelper.DB.getRepository(ReferenceRange);
-		let whereAttr: string[] = [];
-		let whereVal: any = {};
+
+		const query = repo.createQueryBuilder("ReferenceRange");
+
 		if (filter && Object.keys(filter).length > 0) {
-			whereAttr = [...whereAttr, ...CommonHelper.handleQueryFilter(filter).whereAttr];
-			whereVal = { ...whereVal, ...CommonHelper.handleQueryFilter(filter).whereVal };
+			Object.entries(filter).forEach(([key, value]) => {
+				if (value !== undefined && value !== null && value !== "") {
+					query.andWhere(`ReferenceRange.${key} = :${key}`, { [key]: value });
+				}
+			});
 		}
-
-		var query = repo.createQueryBuilder("ReferenceRange");
-		if (whereAttr.length != 0) {
-			query = query.where(whereAttr.join(" and "), whereVal);
-		}
-
+		
 		return query;
 	}
 }