diff --git a/lib/ips.test.js b/lib/ips.test.js
index 5948228..c867e0a 100644
--- a/lib/ips.test.js
+++ b/lib/ips.test.js
@@ -9,14 +9,14 @@ describe('IPS data string generator', () => {
             c: 1,
             v: '01',
             k: 'PR',
-            r: '160000000001006645',
+            r: '123456789012345611',
             i: 'RSD1295,',
             n: 'JEST Ltd., Test',
             rs: 'test-2020',
             sf: '123',
             s: 'Testing'
         };
-        const result = 'K:PR|V:01|C:1|R:160000000001006645|I:RSD1295,|N:JEST Ltd., Test|RS:test-2020|SF:123|S:Testing';
+        const result = 'K:PR|V:01|C:1|R:123456789012345611|I:RSD1295,|N:JEST Ltd., Test|RS:test-2020|SF:123|S:Testing';
         await expect(generateIpsDataString(args)).resolves.toBe(result);
     });
 });
diff --git a/lib/schema.js b/lib/schema.js
index 7e04586..46bb9ed 100644
--- a/lib/schema.js
+++ b/lib/schema.js
@@ -13,6 +13,9 @@ module.exports = yup.object({
   r: yup.string()
     .matches(/^[0-9]{18}$/, "Must contain exactly 18 numeric characters")
     .test('bank-account', "Value is not a valid bank account", value => {
+        if (!value) {
+            return false;
+        }
         const account = parseInt(value.substr(0, 16));
         const control = parseInt(value.substr(16));
         return control === 98 - (account * 100) % 97;
@@ -21,6 +24,9 @@ module.exports = yup.object({
   o: yup.string()
     .matches(/^[0-9]{18}$/, "Must contain exactly 18 numeric characters")
     .test('bank-account', "Value is not a valid bank account", value => {
+        if (!value) {
+            return true;
+        }
         const account = parseInt(value.substr(0, 16));
         const control = parseInt(value.substr(16));
         return control === 98 - (account * 100) % 97;