diff --git a/jetstream/analysis.py b/jetstream/analysis.py
index 4788403c..add50ef2 100644
--- a/jetstream/analysis.py
+++ b/jetstream/analysis.py
@@ -36,12 +36,7 @@
 from jetstream.metric import Metric
 from jetstream.platform import PLATFORM_CONFIGS
 from jetstream.segment import Segment
-from jetstream.statistics import (
-    Count,
-    StatisticResult,
-    StatisticResultCollection,
-    Summary,
-)
+from jetstream.statistics import Count, StatisticResult, StatisticResultCollection, Summary
 
 from . import bq_normalize_name
 
diff --git a/jetstream/statistics.py b/jetstream/statistics.py
index c26586f2..7e07f6e4 100644
--- a/jetstream/statistics.py
+++ b/jetstream/statistics.py
@@ -16,6 +16,7 @@
 import mozanalysis.frequentist_stats.linear_models
 import mozanalysis.metrics
 import numpy as np
+import pandas as pd
 from google.cloud import bigquery
 from metric_config_parser import metric as parser_metric
 from metric_config_parser.experiment import Experiment
@@ -486,7 +487,9 @@ def transform(
 
         if ref_values is not None and not ref_values.empty:
             threshold = df[metric].dropna().quantile(threshold_quantile)
-            if np.issubdtype(df[metric].dtype, np.integer):
+            # use pandas' dtype check so nullable extension dtypes (e.g. Int64) from
+            # BigQuery are handled; np.issubdtype raises on pandas extension dtypes
+            if pd.api.types.is_integer_dtype(df[metric].dtype):
                 threshold = int(np.ceil(threshold))
             post_trim = ref_values.clip(upper=threshold)
 
diff --git a/jetstream/tests/test_config.py b/jetstream/tests/test_config.py
index a767426c..f4ab3264 100644
--- a/jetstream/tests/test_config.py
+++ b/jetstream/tests/test_config.py
@@ -10,11 +10,7 @@
 
 from jetstream.config import ConfigLoader, _ConfigLoader, validate
 from jetstream.dryrun import DryRunFailedError
-from jetstream.platform import (
-    Platform,
-    PlatformConfigurationException,
-    _generate_platform_config,
-)
+from jetstream.platform import Platform, PlatformConfigurationException, _generate_platform_config
 
 
 class TestConfig:
diff --git a/jetstream/tests/test_experimenter.py b/jetstream/tests/test_experimenter.py
index 1d4fe9f0..2405d05b 100644
--- a/jetstream/tests/test_experimenter.py
+++ b/jetstream/tests/test_experimenter.py
@@ -9,12 +9,7 @@
 import pytz
 from metric_config_parser.experiment import Branch, BucketConfig, Experiment
 
-from jetstream.experimenter import (
-    ExperimentCollection,
-    NimbusExperiment,
-    Outcome,
-    Segment,
-)
+from jetstream.experimenter import ExperimentCollection, NimbusExperiment, Outcome, Segment
 
 NIMBUS_EXPERIMENTER_FIXTURE = r"""
 [
diff --git a/jetstream/tests/test_exposure_signal.py b/jetstream/tests/test_exposure_signal.py
index a982d84e..54cbdf82 100644
--- a/jetstream/tests/test_exposure_signal.py
+++ b/jetstream/tests/test_exposure_signal.py
@@ -4,9 +4,7 @@
 import pytest
 import toml
 from metric_config_parser.analysis import AnalysisSpec
-from metric_config_parser.exposure_signal import (
-    ExposureSignal as MetricConfigParserExposureSignal,
-)
+from metric_config_parser.exposure_signal import ExposureSignal as MetricConfigParserExposureSignal
 
 from jetstream.config import ConfigLoader
 from jetstream.exposure_signal import ExposureSignal
diff --git a/jetstream/tests/test_statistics.py b/jetstream/tests/test_statistics.py
index a44aa844..91708720 100644
--- a/jetstream/tests/test_statistics.py
+++ b/jetstream/tests/test_statistics.py
@@ -85,6 +85,25 @@ def test_linear_model_mean(self):
         assert treatment_result.lower
         assert treatment_result.upper
 
+    def test_linear_model_mean_nullable_integer_dtype(self):
+        """Metrics read from BigQuery can have pandas nullable Int64 dtype; the integer-dtype
+        check in transform must not raise 'Cannot interpret Int64Dtype() as a data type'."""
+        stat = LinearModelMean()
+        test_data = pd.DataFrame(
+            {"branch": ["treatment"] * 10 + ["control"] * 10, "value": list(range(20))}
+        )
+        test_data["value"] = test_data["value"].astype("Int64")
+        assert pd.api.types.is_integer_dtype(test_data["value"].dtype)
+
+        results = stat.transform(
+            test_data, "value", "control", None, AnalysisBasis.ENROLLMENTS, "all"
+        ).root
+
+        branch_results = [r for r in results if r.comparison is None]
+        treatment_result = next(r for r in branch_results if r.branch == "treatment")
+        control_result = next(r for r in branch_results if r.branch == "control")
+        assert treatment_result.point < control_result.point
+
     def test_linear_model_mean_all_zero_reference_branch(self, caplog):
         """When the reference branch has no non-zero values, log a clear warning."""
         stat = LinearModelMean()