diff --git a/x-pack/plugins/apm/server/lib/alerts/register_transaction_duration_alert_type.ts b/x-pack/plugins/apm/server/lib/alerts/register_transaction_duration_alert_type.ts
index f3893a9da24c..fedc185d84f9 100644
--- a/x-pack/plugins/apm/server/lib/alerts/register_transaction_duration_alert_type.ts
+++ b/x-pack/plugins/apm/server/lib/alerts/register_transaction_duration_alert_type.ts
@@ -5,9 +5,8 @@
  * 2.0.
  */
 
-import { schema } from '@kbn/config-schema';
-import { take } from 'rxjs/operators';
 import { QueryDslQueryContainer } from '@elastic/elasticsearch/api/types';
+import { schema } from '@kbn/config-schema';
 import type {
   ALERT_EVALUATION_THRESHOLD as ALERT_EVALUATION_THRESHOLD_TYPED,
   ALERT_EVALUATION_VALUE as ALERT_EVALUATION_VALUE_TYPED,
@@ -19,33 +18,36 @@ import {
   ALERT_REASON as ALERT_REASON_NON_TYPED,
   // @ts-expect-error
 } from '@kbn/rule-data-utils/target_node/technical_field_names';
-import { SearchAggregatedTransactionSetting } from '../../../common/aggregated_transactions';
+import { take } from 'rxjs/operators';
 import { asDuration } from '../../../../observability/common/utils/formatters';
 import { createLifecycleRuleTypeFactory } from '../../../../rule_registry/server';
-import {
-  getEnvironmentLabel,
-  getEnvironmentEsField,
-} from '../../../common/environment_filter_values';
+import { SearchAggregatedTransactionSetting } from '../../../common/aggregated_transactions';
 import {
   AlertType,
-  APM_SERVER_FEATURE_ID,
   ALERT_TYPES_CONFIG,
+  APM_SERVER_FEATURE_ID,
   formatTransactionDurationReason,
 } from '../../../common/alert_types';
 import {
   PROCESSOR_EVENT,
   SERVICE_NAME,
-  TRANSACTION_DURATION,
   TRANSACTION_TYPE,
 } from '../../../common/elasticsearch_fieldnames';
+import {
+  getEnvironmentEsField,
+  getEnvironmentLabel,
+} from '../../../common/environment_filter_values';
 import { ProcessorEvent } from '../../../common/processor_event';
-import { getDurationFormatter } from '../../../common/utils/formatters';
 import { environmentQuery } from '../../../common/utils/environment_query';
+import { getDurationFormatter } from '../../../common/utils/formatters';
+import {
+  getDocumentTypeFilterForAggregatedTransactions,
+  getTransactionDurationFieldForAggregatedTransactions,
+} from '../helpers/aggregated_transactions';
 import { getApmIndices } from '../settings/apm_indices/get_apm_indices';
 import { apmActionVariables } from './action_variables';
 import { alertingEsClient } from './alerting_es_client';
 import { RegisterRuleDependencies } from './register_apm_alerts';
-import { getDocumentTypeFilterForAggregatedTransactions } from '../helpers/aggregated_transactions';
 
 const ALERT_EVALUATION_THRESHOLD: typeof ALERT_EVALUATION_THRESHOLD_TYPED = ALERT_EVALUATION_THRESHOLD_NON_TYPED;
 const ALERT_EVALUATION_VALUE: typeof ALERT_EVALUATION_VALUE_TYPED = ALERT_EVALUATION_VALUE_NON_TYPED;
@@ -118,6 +120,10 @@ export function registerTransactionDurationAlertType({
         ? indices['apm_oss.metricsIndices']
         : indices['apm_oss.transactionIndices'];
 
+      const field = getTransactionDurationFieldForAggregatedTransactions(
+        searchAggregatedTransactions
+      );
+
       const searchParams = {
         index,
         body: {
@@ -148,10 +154,10 @@ export function registerTransactionDurationAlertType({
           aggs: {
             latency:
               alertParams.aggregationType === 'avg'
-                ? { avg: { field: TRANSACTION_DURATION } }
+                ? { avg: { field } }
                 : {
                     percentiles: {
-                      field: TRANSACTION_DURATION,
+                      field,
                       percents: [
                         alertParams.aggregationType === '95th' ? 95 : 99,
                       ],