diff --git a/api/v1/group_routes_test.go b/api/v1/group_routes_test.go
index 1a8f5eed8df9..9893d87bfe48 100644
--- a/api/v1/group_routes_test.go
+++ b/api/v1/group_routes_test.go
@@ -44,7 +44,7 @@ func getControlSurface(tb testing.TB, testState *lib.TestRunState) *ControlSurfa
 	execScheduler, err := execution.NewScheduler(testState)
 	require.NoError(tb, err)
 
-	me, err := engine.NewMetricsEngine(testState)
+	me, err := engine.NewMetricsEngine(testState.Registry, testState.Logger)
 	require.NoError(tb, err)
 
 	ctx, cancel := context.WithCancel(context.Background())
diff --git a/api/v1/setup_teardown_routes_test.go b/api/v1/setup_teardown_routes_test.go
index 790b8e14647d..65917e0a8ab7 100644
--- a/api/v1/setup_teardown_routes_test.go
+++ b/api/v1/setup_teardown_routes_test.go
@@ -140,7 +140,7 @@ func TestSetupData(t *testing.T) {
 
 			execScheduler, err := execution.NewScheduler(testState)
 			require.NoError(t, err)
-			metricsEngine, err := engine.NewMetricsEngine(testState)
+			metricsEngine, err := engine.NewMetricsEngine(testState.Registry, testState.Logger)
 			require.NoError(t, err)
 
 			globalCtx, globalCancel := context.WithCancel(context.Background())
diff --git a/api/v1/status_routes_test.go b/api/v1/status_routes_test.go
index 89365b23d489..f74f0ed5a201 100644
--- a/api/v1/status_routes_test.go
+++ b/api/v1/status_routes_test.go
@@ -115,7 +115,7 @@ func TestPatchStatus(t *testing.T) {
 			execScheduler, err := execution.NewScheduler(testState)
 			require.NoError(t, err)
 
-			metricsEngine, err := engine.NewMetricsEngine(testState)
+			metricsEngine, err := engine.NewMetricsEngine(testState.Registry, testState.Logger)
 			require.NoError(t, err)
 
 			globalCtx, globalCancel := context.WithCancel(context.Background())
diff --git a/cmd/run.go b/cmd/run.go
index cd69ed043a75..2c640513c179 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -147,17 +147,28 @@ func (c *cmdRun) run(cmd *cobra.Command, args []string) (err error) {
 		return err
 	}
 
-	executionState := execScheduler.GetState()
-	metricsEngine, err := engine.NewMetricsEngine(executionState.Test)
+	metricsEngine, err := engine.NewMetricsEngine(testRunState.Registry, logger)
 	if err != nil {
 		return err
 	}
-	if !testRunState.RuntimeOptions.NoSummary.Bool || !testRunState.RuntimeOptions.NoThresholds.Bool {
+
+	// We'll need to pipe metrics to the MetricsEngine and process them if any
+	// of these are enabled: thresholds, end-of-test summary
+	shouldProcessMetrics := (!testRunState.RuntimeOptions.NoSummary.Bool ||
+		!testRunState.RuntimeOptions.NoThresholds.Bool)
+	var metricsIngester *engine.OutputIngester
+	if shouldProcessMetrics {
+		err = metricsEngine.InitSubMetricsAndThresholds(conf.Options, testRunState.RuntimeOptions.NoThresholds.Bool)
+		if err != nil {
+			return err
+		}
 		// We'll need to pipe metrics to the MetricsEngine if either the
 		// thresholds or the end-of-test summary are enabled.
-		outputs = append(outputs, metricsEngine.CreateIngester())
+		metricsIngester = metricsEngine.CreateIngester()
+		outputs = append(outputs, metricsIngester)
 	}
 
+	executionState := execScheduler.GetState()
 	if !testRunState.RuntimeOptions.NoSummary.Bool {
 		defer func() {
 			logger.Debug("Generating the end-of-test summary...")
@@ -208,7 +219,9 @@ func (c *cmdRun) run(cmd *cobra.Command, args []string) (err error) {
 	}()
 
 	if !testRunState.RuntimeOptions.NoThresholds.Bool {
-		finalizeThresholds := metricsEngine.StartThresholdCalculations(runAbort, executionState.GetCurrentTestRunDuration)
+		finalizeThresholds := metricsEngine.StartThresholdCalculations(
+			metricsIngester, runAbort, executionState.GetCurrentTestRunDuration,
+		)
 		handleFinalThresholdCalculation := func() {
 			// This gets called after the Samples channel has been closed and
 			// the OutputManager has flushed all of the cached samples to
@@ -283,7 +296,7 @@ func (c *cmdRun) run(cmd *cobra.Command, args []string) (err error) {
 	}
 
 	printExecutionDescription(
-		c.gs, "local", args[0], "", conf, execScheduler.GetState().ExecutionTuple, executionPlan, outputs,
+		c.gs, "local", args[0], "", conf, executionState.ExecutionTuple, executionPlan, outputs,
 	)
 
 	// Trap Interrupts, SIGINTs and SIGTERMs.
diff --git a/execution/scheduler.go b/execution/scheduler.go
index 8a5f18bef58b..5469e452d6c1 100644
--- a/execution/scheduler.go
+++ b/execution/scheduler.go
@@ -377,7 +377,7 @@ func (e *Scheduler) runExecutor(
 // and emission of the `vus` and `vus_max` metrics.
 func (e *Scheduler) Init(
 	runCtx context.Context, samplesOut chan<- metrics.SampleContainer,
-) (stopVUEmission func(), err error) {
+) (stopVUEmission func(), initErr error) {
 	logger := e.state.Test.Logger.WithField("phase", "execution-scheduler-init")
 
 	execSchedRunCtx, execSchedRunCancel := context.WithCancel(runCtx)
@@ -390,11 +390,11 @@ func (e *Scheduler) Init(
 
 	defer func() {
 		if interruptErr := GetCancelReasonIfTestAborted(runCtx); interruptErr != nil {
-			logger.Debugf("The test run was interrupted, returning '%s' instead of '%s'", interruptErr, err)
+			logger.Debugf("The test run was interrupted, returning '%s' instead of '%s'", interruptErr, initErr)
 			e.state.SetExecutionStatus(lib.ExecutionStatusInterrupted)
-			err = interruptErr
+			initErr = interruptErr
 		}
-		if err != nil {
+		if initErr != nil {
 			stopVUEmission()
 		}
 	}()
@@ -406,14 +406,14 @@ func (e *Scheduler) Init(
 // out channel.
 //
 //nolint:funlen
-func (e *Scheduler) Run(globalCtx, runCtx context.Context, samplesOut chan<- metrics.SampleContainer) (err error) {
+func (e *Scheduler) Run(globalCtx, runCtx context.Context, samplesOut chan<- metrics.SampleContainer) (runErr error) {
 	logger := e.state.Test.Logger.WithField("phase", "execution-scheduler-run")
 
 	defer func() {
 		if interruptErr := GetCancelReasonIfTestAborted(runCtx); interruptErr != nil {
-			logger.Debugf("The test run was interrupted, returning '%s' instead of '%s'", interruptErr, err)
+			logger.Debugf("The test run was interrupted, returning '%s' instead of '%s'", interruptErr, runErr)
 			e.state.SetExecutionStatus(lib.ExecutionStatusInterrupted)
-			err = interruptErr
+			runErr = interruptErr
 		}
 	}()
 
diff --git a/js/runner_test.go b/js/runner_test.go
index ed72b9828d34..4b34dcd16412 100644
--- a/js/runner_test.go
+++ b/js/runner_test.go
@@ -47,7 +47,6 @@ import (
 	"go.k6.io/k6/lib/testutils/mockoutput"
 	"go.k6.io/k6/lib/types"
 	"go.k6.io/k6/metrics"
-	"go.k6.io/k6/metrics/engine"
 	"go.k6.io/k6/output"
 )
 
@@ -387,23 +386,17 @@ func TestDataIsolation(t *testing.T) {
 	execScheduler, err := execution.NewScheduler(testRunState)
 	require.NoError(t, err)
 
-	metricsEngine, err := engine.NewMetricsEngine(testRunState)
-	require.NoError(t, err)
-
 	globalCtx, globalCancel := context.WithCancel(context.Background())
 	defer globalCancel()
 	runCtx, runAbort := execution.NewTestRunContext(globalCtx, testRunState.Logger)
 
 	mockOutput := mockoutput.New()
-	outputManager := output.NewManager([]output.Output{mockOutput, metricsEngine.CreateIngester()}, testRunState.Logger, runAbort)
+	outputManager := output.NewManager([]output.Output{mockOutput}, testRunState.Logger, runAbort)
 	samples := make(chan metrics.SampleContainer, 1000)
 	waitForMetricsFlushed, stopOutputs, err := outputManager.Start(samples)
 	require.NoError(t, err)
 	defer stopOutputs(nil)
 
-	finalizeThresholds := metricsEngine.StartThresholdCalculations(runAbort, execScheduler.GetState().GetCurrentTestRunDuration)
-	require.Nil(t, finalizeThresholds)
-
 	require.Empty(t, runner.defaultGroup.Groups)
 
 	stopEmission, err := execScheduler.Init(runCtx, samples)
diff --git a/js/summary_test.go b/js/summary_test.go
index 2f30669a0d43..a43f68aa4b0d 100644
--- a/js/summary_test.go
+++ b/js/summary_test.go
@@ -150,7 +150,7 @@ func createTestMetrics(t *testing.T) (map[string]*metrics.Metric, *lib.Group) {
 	require.NoError(t, err)
 	checksMetric.Tainted = null.BoolFrom(false)
 	checksMetric.Thresholds = metrics.Thresholds{Thresholds: []*metrics.Threshold{{Source: "rate>70", LastFailed: false}}}
-	sink := &metrics.TrendSink{}
+	sink := metrics.NewTrendSink()
 
 	samples := []float64{10.0, 15.0, 20.0}
 	for _, s := range samples {
diff --git a/metrics/engine/engine.go b/metrics/engine/engine.go
index 8aa81c11fad8..55f0b87fdb74 100644
--- a/metrics/engine/engine.go
+++ b/metrics/engine/engine.go
@@ -15,7 +15,6 @@ import (
 	"go.k6.io/k6/errext/exitcodes"
 	"go.k6.io/k6/lib"
 	"go.k6.io/k6/metrics"
-	"go.k6.io/k6/output"
 	"gopkg.in/guregu/null.v3"
 )
 
@@ -25,13 +24,11 @@ const thresholdsRate = 2 * time.Second
 // aggregated metric sample values. They are used to generate the end-of-test
 // summary and to evaluate the test thresholds.
 type MetricsEngine struct {
-	logger         logrus.FieldLogger
-	test           *lib.TestRunState
-	outputIngester *outputIngester
+	registry *metrics.Registry
+	logger   logrus.FieldLogger
 
 	// These can be both top-level metrics or sub-metrics
-	metricsWithThresholds []*metrics.Metric
-
+	metricsWithThresholds   []*metrics.Metric
 	breachedThresholdsCount uint32
 
 	// TODO: completely refactor:
@@ -44,39 +41,31 @@ type MetricsEngine struct {
 }
 
 // NewMetricsEngine creates a new metrics Engine with the given parameters.
-func NewMetricsEngine(runState *lib.TestRunState) (*MetricsEngine, error) {
+func NewMetricsEngine(registry *metrics.Registry, logger logrus.FieldLogger) (*MetricsEngine, error) {
 	me := &MetricsEngine{
-		test:            runState,
-		logger:          runState.Logger.WithField("component", "metrics-engine"),
+		registry:        registry,
+		logger:          logger.WithField("component", "metrics-engine"),
 		ObservedMetrics: make(map[string]*metrics.Metric),
 	}
 
-	if !(me.test.RuntimeOptions.NoSummary.Bool && me.test.RuntimeOptions.NoThresholds.Bool) {
-		err := me.initSubMetricsAndThresholds()
-		if err != nil {
-			return nil, err
-		}
-	}
-
 	return me, nil
 }
 
 // CreateIngester returns a pseudo-Output that uses the given metric samples to
 // update the engine's inner state.
-func (me *MetricsEngine) CreateIngester() output.Output {
-	me.outputIngester = &outputIngester{
+func (me *MetricsEngine) CreateIngester() *OutputIngester {
+	return &OutputIngester{
 		logger:        me.logger.WithField("component", "metrics-engine-ingester"),
 		metricsEngine: me,
 		cardinality:   newCardinalityControl(),
 	}
-	return me.outputIngester
 }
 
 func (me *MetricsEngine) getThresholdMetricOrSubmetric(name string) (*metrics.Metric, error) {
 	// TODO: replace with strings.Cut after Go 1.18
 	nameParts := strings.SplitN(name, "{", 2)
 
-	metric := me.test.Registry.Get(nameParts[0])
+	metric := me.registry.Get(nameParts[0])
 	if metric == nil {
 		return nil, fmt.Errorf("metric '%s' does not exist in the script", nameParts[0])
 	}
@@ -125,11 +114,14 @@ func (me *MetricsEngine) markObserved(metric *metrics.Metric) {
 	}
 }
 
-func (me *MetricsEngine) initSubMetricsAndThresholds() error {
-	for metricName, thresholds := range me.test.Options.Thresholds {
+// InitSubMetricsAndThresholds parses the thresholds from the test Options and
+// initializes both the thresholds themselves, as well as any submetrics that
+// were referenced in them.
+func (me *MetricsEngine) InitSubMetricsAndThresholds(options lib.Options, onlyLogErrors bool) error {
+	for metricName, thresholds := range options.Thresholds {
 		metric, err := me.getThresholdMetricOrSubmetric(metricName)
 
-		if me.test.RuntimeOptions.NoThresholds.Bool {
+		if onlyLogErrors {
 			if err != nil {
 				me.logger.WithError(err).Warnf("Invalid metric '%s' in threshold definitions", metricName)
 			}
@@ -154,7 +146,7 @@ func (me *MetricsEngine) initSubMetricsAndThresholds() error {
 
 	// TODO: refactor out of here when https://github.com/grafana/k6/issues/1321
 	// lands and there is a better way to enable a metric with tag
-	if me.test.Options.SystemTags.Has(metrics.TagExpectedResponse) {
+	if options.SystemTags.Has(metrics.TagExpectedResponse) {
 		_, err := me.getThresholdMetricOrSubmetric("http_req_duration{expected_response:true}")
 		if err != nil {
 			return err // shouldn't happen, but ¯\_(ツ)_/¯
@@ -167,10 +159,10 @@ func (me *MetricsEngine) initSubMetricsAndThresholds() error {
 // StartThresholdCalculations spins up a new goroutine to crunch thresholds and
 // returns a callback that will stop the goroutine and finalizes calculations.
 func (me *MetricsEngine) StartThresholdCalculations(
+	ingester *OutputIngester,
 	abortRun func(error),
 	getCurrentTestRunDuration func() time.Duration,
-) (finalize func() (breached []string),
-) {
+) (finalize func() (breached []string)) {
 	if len(me.metricsWithThresholds) == 0 {
 		return nil // no thresholds were defined
 	}
@@ -205,9 +197,9 @@ func (me *MetricsEngine) StartThresholdCalculations(
 	}()
 
 	return func() []string {
-		if me.outputIngester != nil {
+		if ingester != nil {
 			// Stop the ingester so we don't get any more metrics
-			err := me.outputIngester.Stop()
+			err := ingester.Stop()
 			if err != nil {
 				me.logger.WithError(err).Warnf("There was a problem stopping the output ingester.")
 			}
diff --git a/metrics/engine/engine_test.go b/metrics/engine/engine_test.go
index 06267cfa3c86..a941b4671b84 100644
--- a/metrics/engine/engine_test.go
+++ b/metrics/engine/engine_test.go
@@ -32,10 +32,12 @@ func TestNewMetricsEngineWithThresholds(t *testing.T) {
 	_, err = trs.Registry.NewMetric("metric2", metrics.Counter)
 	require.NoError(t, err)
 
-	me, err := NewMetricsEngine(trs)
+	me, err := NewMetricsEngine(trs.Registry, trs.Logger)
 	require.NoError(t, err)
 	require.NotNil(t, me)
 
+	require.NoError(t, me.InitSubMetricsAndThresholds(trs.Options, false))
+
 	assert.Len(t, me.metricsWithThresholds, 2)
 }
 
@@ -57,7 +59,7 @@ func TestMetricsEngineGetThresholdMetricOrSubmetricError(t *testing.T) {
 			t.Parallel()
 
 			me := newTestMetricsEngine(t)
-			_, err := me.test.Registry.NewMetric("metric1", metrics.Counter)
+			_, err := me.registry.NewMetric("metric1", metrics.Counter)
 			require.NoError(t, err)
 
 			_, err = me.getThresholdMetricOrSubmetric(tc.metricDefinition)
@@ -69,16 +71,8 @@ func TestMetricsEngineGetThresholdMetricOrSubmetricError(t *testing.T) {
 func TestNewMetricsEngineNoThresholds(t *testing.T) {
 	t.Parallel()
 
-	trs := &lib.TestRunState{
-		TestPreInitState: &lib.TestPreInitState{
-			Logger: testutils.NewLogger(t),
-		},
-	}
-
-	me, err := NewMetricsEngine(trs)
-	require.NoError(t, err)
+	me := newTestMetricsEngine(t)
 	require.NotNil(t, me)
-
 	assert.Empty(t, me.metricsWithThresholds)
 }
 
@@ -113,9 +107,9 @@ func TestMetricsEngineEvaluateThresholdNoAbort(t *testing.T) {
 			t.Parallel()
 			me := newTestMetricsEngine(t)
 
-			m1, err := me.test.Registry.NewMetric("m1", metrics.Counter)
+			m1, err := me.registry.NewMetric("m1", metrics.Counter)
 			require.NoError(t, err)
-			m2, err := me.test.Registry.NewMetric("m2", metrics.Counter)
+			m2, err := me.registry.NewMetric("m2", metrics.Counter)
 			require.NoError(t, err)
 
 			ths := metrics.NewThresholds([]string{tc.threshold})
@@ -138,9 +132,9 @@ func TestMetricsEngineEvaluateIgnoreEmptySink(t *testing.T) {
 
 	me := newTestMetricsEngine(t)
 
-	m1, err := me.test.Registry.NewMetric("m1", metrics.Counter)
+	m1, err := me.registry.NewMetric("m1", metrics.Counter)
 	require.NoError(t, err)
-	m2, err := me.test.Registry.NewMetric("m2", metrics.Counter)
+	m2, err := me.registry.NewMetric("m2", metrics.Counter)
 	require.NoError(t, err)
 
 	ths := metrics.NewThresholds([]string{"count>5"})
@@ -159,18 +153,10 @@ func TestMetricsEngineEvaluateIgnoreEmptySink(t *testing.T) {
 	assert.Empty(t, breached)
 }
 
-func newTestMetricsEngine(t *testing.T) MetricsEngine {
-	trs := &lib.TestRunState{
-		TestPreInitState: &lib.TestPreInitState{
-			Logger:   testutils.NewLogger(t),
-			Registry: metrics.NewRegistry(),
-		},
-	}
-
-	return MetricsEngine{
-		logger: trs.Logger,
-		test:   trs,
-	}
+func newTestMetricsEngine(t *testing.T) *MetricsEngine {
+	m, err := NewMetricsEngine(metrics.NewRegistry(), testutils.NewLogger(t))
+	require.NoError(t, err)
+	return m
 }
 
 func zeroTestRunDuration() time.Duration {
diff --git a/metrics/engine/ingester.go b/metrics/engine/ingester.go
index 62ffee8293e6..496b6a6eaa74 100644
--- a/metrics/engine/ingester.go
+++ b/metrics/engine/ingester.go
@@ -13,16 +13,16 @@ const (
 	timeSeriesFirstLimit = 100_000
 )
 
-var _ output.Output = &outputIngester{}
+var _ output.Output = &OutputIngester{}
 
 // IngesterDescription is a short description for ingester.
 // This variable is used from a function in cmd/ui file for matching this output
 // and print a special text.
 const IngesterDescription = "Internal Metrics Ingester"
 
-// outputIngester implements the output.Output interface and can be used to
+// OutputIngester implements the output.Output interface and can be used to
 // "feed" the MetricsEngine data from a `k6 run` test run.
-type outputIngester struct {
+type OutputIngester struct {
 	output.SampleBuffer
 	logger logrus.FieldLogger
 
@@ -32,12 +32,12 @@ type outputIngester struct {
 }
 
 // Description returns a human-readable description of the output.
-func (oi *outputIngester) Description() string {
+func (oi *OutputIngester) Description() string {
 	return IngesterDescription
 }
 
 // Start the engine by initializing a new output.PeriodicFlusher
-func (oi *outputIngester) Start() error {
+func (oi *OutputIngester) Start() error {
 	oi.logger.Debug("Starting...")
 
 	pf, err := output.NewPeriodicFlusher(collectRate, oi.flushMetrics)
@@ -51,7 +51,7 @@ func (oi *outputIngester) Start() error {
 }
 
 // Stop flushes any remaining metrics and stops the goroutine.
-func (oi *outputIngester) Stop() error {
+func (oi *OutputIngester) Stop() error {
 	oi.logger.Debug("Stopping...")
 	defer oi.logger.Debug("Stopped!")
 	oi.periodicFlusher.Stop()
@@ -59,7 +59,7 @@ func (oi *outputIngester) Stop() error {
 }
 
 // flushMetrics Writes samples to the MetricsEngine
-func (oi *outputIngester) flushMetrics() {
+func (oi *OutputIngester) flushMetrics() {
 	sampleContainers := oi.GetBufferedSamples()
 	if len(sampleContainers) == 0 {
 		return
diff --git a/metrics/engine/ingester_test.go b/metrics/engine/ingester_test.go
index 71f7a7c84973..b299322e363b 100644
--- a/metrics/engine/ingester_test.go
+++ b/metrics/engine/ingester_test.go
@@ -19,7 +19,7 @@ func TestIngesterOutputFlushMetrics(t *testing.T) {
 	testMetric, err := piState.Registry.NewMetric("test_metric", metrics.Trend)
 	require.NoError(t, err)
 
-	ingester := outputIngester{
+	ingester := OutputIngester{
 		logger: piState.Logger,
 		metricsEngine: &MetricsEngine{
 			ObservedMetrics: make(map[string]*metrics.Metric),
@@ -55,9 +55,8 @@ func TestIngesterOutputFlushSubmetrics(t *testing.T) {
 	require.NoError(t, err)
 
 	me := &MetricsEngine{
-		test: &lib.TestRunState{
-			TestPreInitState: piState,
-		},
+		logger:          piState.Logger,
+		registry:        piState.Registry,
 		ObservedMetrics: make(map[string]*metrics.Metric),
 	}
 	_, err = me.getThresholdMetricOrSubmetric("test_metric{a:1}")
@@ -66,7 +65,7 @@ func TestIngesterOutputFlushSubmetrics(t *testing.T) {
 	// assert that observed metrics is empty before to start
 	require.Empty(t, me.ObservedMetrics)
 
-	ingester := outputIngester{
+	ingester := OutputIngester{
 		logger:        piState.Logger,
 		metricsEngine: me,
 		cardinality:   newCardinalityControl(),
@@ -107,7 +106,7 @@ func TestOutputFlushMetricsTimeSeriesWarning(t *testing.T) {
 	require.NoError(t, err)
 
 	logger, hook := testutils.NewLoggerWithHook(nil)
-	ingester := outputIngester{
+	ingester := OutputIngester{
 		logger: logger,
 		metricsEngine: &MetricsEngine{
 			ObservedMetrics: make(map[string]*metrics.Metric),
diff --git a/metrics/metric_test.go b/metrics/metric_test.go
index 4b29ebe54e7a..cfd2d7510227 100644
--- a/metrics/metric_test.go
+++ b/metrics/metric_test.go
@@ -15,7 +15,7 @@ func TestNewMetric(t *testing.T) {
 	}{
 		"Counter": {Counter, &CounterSink{}},
 		"Gauge":   {Gauge, &GaugeSink{}},
-		"Trend":   {Trend, &TrendSink{}},
+		"Trend":   {Trend, NewTrendSink()},
 		"Rate":    {Rate, &RateSink{}},
 	}
 
diff --git a/metrics/sample.go b/metrics/sample.go
index 81c1a942afdf..3d1e873821bd 100644
--- a/metrics/sample.go
+++ b/metrics/sample.go
@@ -140,11 +140,11 @@ func PushIfNotDone(ctx context.Context, output chan<- SampleContainer, sample Sa
 // the summary output and then returns a map of the corresponding resolvers.
 func GetResolversForTrendColumns(trendColumns []string) (map[string]func(s *TrendSink) float64, error) {
 	staticResolvers := map[string]func(s *TrendSink) float64{
-		"avg":   func(s *TrendSink) float64 { return s.Avg },
-		"min":   func(s *TrendSink) float64 { return s.Min },
+		"avg":   func(s *TrendSink) float64 { return s.Avg() },
+		"min":   func(s *TrendSink) float64 { return s.Min() },
 		"med":   func(s *TrendSink) float64 { return s.P(0.5) },
-		"max":   func(s *TrendSink) float64 { return s.Max },
-		"count": func(s *TrendSink) float64 { return float64(s.Count) },
+		"max":   func(s *TrendSink) float64 { return s.Max() },
+		"count": func(s *TrendSink) float64 { return float64(s.Count()) },
 	}
 	dynamicResolver := func(percentile float64) func(s *TrendSink) float64 {
 		return func(s *TrendSink) float64 {
diff --git a/metrics/sample_test.go b/metrics/sample_test.go
index 2c2042f7f323..f5654e7ea7a5 100644
--- a/metrics/sample_test.go
+++ b/metrics/sample_test.go
@@ -99,11 +99,11 @@ func TestGetResolversForTrendColumnsCalculation(t *testing.T) {
 }
 
 func createTestTrendSink(count int) *TrendSink {
-	sink := TrendSink{}
+	sink := NewTrendSink()
 
 	for i := 0; i < count; i++ {
 		sink.Add(Sample{Value: float64(i)})
 	}
 
-	return &sink
+	return sink
 }
diff --git a/metrics/sink.go b/metrics/sink.go
index e238dae78507..046a6bfee6ae 100644
--- a/metrics/sink.go
+++ b/metrics/sink.go
@@ -1,7 +1,6 @@
 package metrics
 
 import (
-	"errors"
 	"fmt"
 	"math"
 	"sort"
@@ -11,9 +10,8 @@ import (
 var (
 	_ Sink = &CounterSink{}
 	_ Sink = &GaugeSink{}
-	_ Sink = &TrendSink{}
+	_ Sink = NewTrendSink()
 	_ Sink = &RateSink{}
-	_ Sink = &DummySink{}
 )
 
 type Sink interface {
@@ -32,7 +30,7 @@ func NewSink(mt MetricType) Sink {
 	case Gauge:
 		sink = &GaugeSink{}
 	case Trend:
-		sink = &TrendSink{}
+		sink = NewTrendSink()
 	case Rate:
 		sink = &RateSink{}
 	default:
@@ -90,67 +88,101 @@ func (g *GaugeSink) Format(t time.Duration) map[string]float64 {
 	return map[string]float64{"value": g.Value}
 }
 
+// NewTrendSink makes a Trend sink with the OpenHistogram circllhist histogram.
+func NewTrendSink() *TrendSink {
+	return &TrendSink{}
+}
+
 type TrendSink struct {
-	Values []float64
+	values []float64
 	sorted bool
 
-	Count    uint64
-	Min, Max float64
-	Sum, Avg float64
+	count    uint64
+	min, max float64
+	// TODO: unexport after this dependency is removed:
+	// https://github.com/grafana/xk6-output-prometheus-remote/blob/v0.2.1/pkg/remotewrite/remotewrite.go#L173
+	Sum float64
 }
 
 // IsEmpty indicates whether the TrendSink is empty.
-func (t *TrendSink) IsEmpty() bool { return t.Count == 0 }
+func (t *TrendSink) IsEmpty() bool { return t.count == 0 }
 
 func (t *TrendSink) Add(s Sample) {
-	if t.Count == 0 {
-		t.Max, t.Min = s.Value, s.Value
+	if t.count == 0 {
+		t.max, t.min = s.Value, s.Value
 	} else {
-		if s.Value > t.Max {
-			t.Max = s.Value
+		if s.Value > t.max {
+			t.max = s.Value
 		}
-		if s.Value < t.Min {
-			t.Min = s.Value
+		if s.Value < t.min {
+			t.min = s.Value
 		}
 	}
 
-	t.Values = append(t.Values, s.Value)
+	t.values = append(t.values, s.Value)
 	t.sorted = false
-	t.Count += 1
+	t.count++
 	t.Sum += s.Value
-	t.Avg = t.Sum / float64(t.Count)
 }
 
 // P calculates the given percentile from sink values.
 func (t *TrendSink) P(pct float64) float64 {
-	switch t.Count {
+	switch t.count {
 	case 0:
 		return 0
 	case 1:
-		return t.Values[0]
+		return t.values[0]
 	default:
 		if !t.sorted {
-			sort.Float64s(t.Values)
+			sort.Float64s(t.values)
 			t.sorted = true
 		}
 
 		// If percentile falls on a value in Values slice, we return that value.
 		// If percentile does not fall on a value in Values slice, we calculate (linear interpolation)
 		// the value that would fall at percentile, given the values above and below that percentile.
-		i := pct * (float64(t.Count) - 1.0)
-		j := t.Values[int(math.Floor(i))]
-		k := t.Values[int(math.Ceil(i))]
+		i := pct * (float64(t.count) - 1.0)
+		j := t.values[int(math.Floor(i))]
+		k := t.values[int(math.Ceil(i))]
 		f := i - math.Floor(i)
 		return j + (k-j)*f
 	}
 }
 
+// Min returns the minimum value.
+func (t *TrendSink) Min() float64 {
+	return t.min
+}
+
+// Max returns the maximum value.
+func (t *TrendSink) Max() float64 {
+	return t.max
+}
+
+// Count returns the number of recorded values.
+func (t *TrendSink) Count() uint64 {
+	return t.count
+}
+
+// Avg returns the average (i.e. mean) value.
+func (t *TrendSink) Avg() float64 {
+	if t.count > 0 {
+		return t.Sum / float64(t.count)
+	}
+	return 0
+}
+
+// Total returns the total (i.e. "sum") value for all measurements.
+func (t *TrendSink) Total() float64 {
+	return t.Sum
+}
+
 func (t *TrendSink) Format(tt time.Duration) map[string]float64 {
 	// TODO: respect the summaryTrendStats for REST API
 	return map[string]float64{
-		"min":   t.Min,
-		"max":   t.Max,
-		"avg":   t.Avg,
+		"min":   t.Min(),
+		"max":   t.Max(),
+		"avg":   t.Avg(),
 		"med":   t.P(0.5),
 		"p(90)": t.P(0.90),
 		"p(95)": t.P(0.95),
@@ -180,16 +212,3 @@ func (r RateSink) Format(t time.Duration) map[string]float64 {
 
 	return map[string]float64{"rate": rate}
 }
-
-type DummySink map[string]float64
-
-// IsEmpty indicates whether the DummySink is empty.
-func (d DummySink) IsEmpty() bool { return len(d) == 0 }
-
-func (d DummySink) Add(s Sample) {
-	panic(errors.New("you can't add samples to a dummy sink"))
-}
-
-func (d DummySink) Format(t time.Duration) map[string]float64 {
-	return map[string]float64(d)
-}
diff --git a/metrics/sink_test.go b/metrics/sink_test.go
index ddf7081267d3..5f872e70e9a1 100644
--- a/metrics/sink_test.go
+++ b/metrics/sink_test.go
@@ -19,7 +19,7 @@ func TestNewSink(t *testing.T) {
 		{mt: Counter, sink: &CounterSink{}},
 		{mt: Gauge, sink: &GaugeSink{}},
 		{mt: Rate, sink: &RateSink{}},
-		{mt: Trend, sink: &TrendSink{}},
+		{mt: Trend, sink: NewTrendSink()},
 	}
 	for _, tc := range tests {
 		assert.Equal(t, tc.sink, NewSink(tc.mt))
@@ -101,56 +101,56 @@ func TestTrendSink(t *testing.T) {
 		t.Run("one value", func(t *testing.T) {
 			t.Parallel()
 
-			sink := TrendSink{}
+			sink := NewTrendSink()
 			sink.Add(Sample{TimeSeries: TimeSeries{Metric: &Metric{}}, Value: 7.0})
-			assert.Equal(t, uint64(1), sink.Count)
-			assert.Equal(t, 7.0, sink.Min)
-			assert.Equal(t, 7.0, sink.Max)
-			assert.Equal(t, 7.0, sink.Avg)
-			assert.Equal(t, 7.0, sink.Sum)
-			assert.Equal(t, []float64{7.0}, sink.Values)
+			assert.Equal(t, uint64(1), sink.Count())
+			assert.Equal(t, 7.0, sink.Min())
+			assert.Equal(t, 7.0, sink.Max())
+			assert.Equal(t, 7.0, sink.Avg())
+			assert.Equal(t, 7.0, sink.Total())
+			assert.Equal(t, []float64{7.0}, sink.values)
 		})
 		t.Run("values", func(t *testing.T) {
 			t.Parallel()
 
-			sink := TrendSink{}
+			sink := NewTrendSink()
 			for _, s := range unsortedSamples10 {
 				sink.Add(Sample{TimeSeries: TimeSeries{Metric: &Metric{}}, Value: s})
 			}
-			assert.Equal(t, uint64(len(unsortedSamples10)), sink.Count)
-			assert.Equal(t, 0.0, sink.Min)
-			assert.Equal(t, 100.0, sink.Max)
-			assert.Equal(t, 54.0, sink.Avg)
-			assert.Equal(t, 540.0, sink.Sum)
-			assert.Equal(t, unsortedSamples10, sink.Values)
+			assert.Equal(t, uint64(len(unsortedSamples10)), sink.Count())
+			assert.Equal(t, 0.0, sink.Min())
+			assert.Equal(t, 100.0, sink.Max())
+			assert.Equal(t, 54.0, sink.Avg())
+			assert.Equal(t, 540.0, sink.Total())
+			assert.Equal(t, unsortedSamples10, sink.values)
 		})
 		t.Run("negative", func(t *testing.T) {
 			t.Parallel()
 
-			sink := TrendSink{}
+			sink := NewTrendSink()
 			for _, s := range []float64{-10, -20} {
 				sink.Add(Sample{TimeSeries: TimeSeries{Metric: &Metric{}}, Value: s})
 			}
-			assert.Equal(t, uint64(2), sink.Count)
-			assert.Equal(t, -20.0, sink.Min)
-			assert.Equal(t, -10.0, sink.Max)
-			assert.Equal(t, -15.0, sink.Avg)
-			assert.Equal(t, -30.0, sink.Sum)
-			assert.Equal(t, []float64{-10, -20}, sink.Values)
+			assert.Equal(t, uint64(2), sink.Count())
+			assert.Equal(t, -20.0, sink.Min())
+			assert.Equal(t, -10.0, sink.Max())
+			assert.Equal(t, -15.0, sink.Avg())
+			assert.Equal(t, -30.0, sink.Total())
+			assert.Equal(t, []float64{-10, -20}, sink.values)
 		})
 		t.Run("mixed", func(t *testing.T) {
 			t.Parallel()
 
-			sink := TrendSink{}
+			sink := NewTrendSink()
 			for _, s := range []float64{1.4, 0, -1.2} {
 				sink.Add(Sample{TimeSeries: TimeSeries{Metric: &Metric{}}, Value: s})
 			}
-			assert.Equal(t, uint64(3), sink.Count)
-			assert.Equal(t, -1.2, sink.Min)
-			assert.Equal(t, 1.4, sink.Max)
-			assert.Equal(t, 0.067, math.Round(sink.Avg*1000)/1000)
-			assert.Equal(t, 0.199, math.Floor(sink.Sum*1000)/1000)
-			assert.Equal(t, []float64{1.4, 0, -1.2}, sink.Values)
+			assert.Equal(t, uint64(3), sink.Count())
+			assert.Equal(t, -1.2, sink.Min())
+			assert.Equal(t, 1.4, sink.Max())
+			assert.Equal(t, 0.067, math.Round(sink.Avg()*1000)/1000)
+			assert.Equal(t, 0.199, math.Floor(sink.Total()*1000)/1000)
+			assert.Equal(t, []float64{1.4, 0, -1.2}, sink.values)
 		})
 	})
 
@@ -159,7 +159,7 @@ func TestTrendSink(t *testing.T) {
 		t.Run("no values", func(t *testing.T) {
 			t.Parallel()
 
-			sink := TrendSink{}
+			sink := NewTrendSink()
 			for i := 1; i <= 100; i++ {
 				assert.Equal(t, 0.0, sink.P(float64(i)/100.0))
 			}
@@ -167,7 +167,7 @@ func TestTrendSink(t *testing.T) {
 		t.Run("one value", func(t *testing.T) {
 			t.Parallel()
 
-			sink := TrendSink{}
+			sink := NewTrendSink()
 			sink.Add(Sample{TimeSeries: TimeSeries{Metric: &Metric{}}, Value: 10.0})
 			for i := 1; i <= 100; i++ {
 				assert.Equal(t, 10.0, sink.P(float64(i)/100.0))
@@ -176,7 +176,7 @@ func TestTrendSink(t *testing.T) {
 		t.Run("two values", func(t *testing.T) {
 			t.Parallel()
 
-			sink := TrendSink{}
+			sink := NewTrendSink()
 			sink.Add(Sample{TimeSeries: TimeSeries{Metric: &Metric{}}, Value: 5.0})
 			sink.Add(Sample{TimeSeries: TimeSeries{Metric: &Metric{}}, Value: 10.0})
 			assert.Equal(t, false, sink.sorted)
@@ -190,7 +190,7 @@ func TestTrendSink(t *testing.T) {
 		t.Run("more than 2", func(t *testing.T) {
 			t.Parallel()
 
-			sink := TrendSink{}
+			sink := NewTrendSink()
 			for _, s := range unsortedSamples10 {
 				sink.Add(Sample{TimeSeries: TimeSeries{Metric: &Metric{}}, Value: s})
 			}
@@ -205,7 +205,7 @@ func TestTrendSink(t *testing.T) {
 	t.Run("format", func(t *testing.T) {
 		t.Parallel()
 
-		sink := TrendSink{}
+		sink := NewTrendSink()
 		for _, s := range unsortedSamples10 {
 			sink.Add(Sample{TimeSeries: TimeSeries{Metric: &Metric{}}, Value: s})
 		}
@@ -259,13 +259,3 @@ func TestRateSink(t *testing.T) {
 		assert.Equal(t, map[string]float64{"rate": 0.5}, sink.Format(0))
 	})
 }
-
-func TestDummySinkAddPanics(t *testing.T) {
-	assert.Panics(t, func() {
-		DummySink{}.Add(Sample{})
-	})
-}
-
-func TestDummySinkFormatReturnsItself(t *testing.T) {
-	assert.Equal(t, map[string]float64{"a": 1}, DummySink{"a": 1}.Format(0))
-}
diff --git a/metrics/thresholds.go b/metrics/thresholds.go
index a83a5999497c..44badb4a10df 100644
--- a/metrics/thresholds.go
+++ b/metrics/thresholds.go
@@ -185,9 +185,9 @@ func (ts *Thresholds) Run(sink Sink, duration time.Duration) (bool, error) {
 	case *GaugeSink:
 		ts.sinked["value"] = sinkImpl.Value
 	case *TrendSink:
-		ts.sinked["min"] = sinkImpl.Min
-		ts.sinked["max"] = sinkImpl.Max
-		ts.sinked["avg"] = sinkImpl.Avg
+		ts.sinked["min"] = sinkImpl.Min()
+		ts.sinked["max"] = sinkImpl.Max()
+		ts.sinked["avg"] = sinkImpl.Avg()
 		ts.sinked["med"] = sinkImpl.P(0.5)
 
 		// Parse the percentile thresholds and insert them in
@@ -206,10 +206,6 @@ func (ts *Thresholds) Run(sink Sink, duration time.Duration) (bool, error) {
 		if sinkImpl.Total > 0 {
 			ts.sinked["rate"] = float64(sinkImpl.Trues) / float64(sinkImpl.Total)
 		}
-	case DummySink:
-		for k, v := range sinkImpl {
-			ts.sinked[k] = v
-		}
 	default:
 		return false, fmt.Errorf("unable to run Thresholds; reason: unknown sink type")
 	}
diff --git a/metrics/thresholds_test.go b/metrics/thresholds_test.go
index 9ee02127d8c3..21faa24a607e 100644
--- a/metrics/thresholds_test.go
+++ b/metrics/thresholds_test.go
@@ -639,6 +639,14 @@ func TestThresholdsRunAll(t *testing.T) {
 	}
 }
 
+func getTrendSink(values ...float64) *TrendSink {
+	sink := NewTrendSink()
+	for _, v := range values {
+		sink.Add(Sample{Value: v})
+	}
+	return sink
+}
+
 func TestThresholdsRun(t *testing.T) {
 	t.Parallel()
 
@@ -656,8 +664,8 @@ func TestThresholdsRun(t *testing.T) {
 		{
 			name: "Running thresholds of existing sink",
 			args: args{
-				sink:                 DummySink{"p(95)": 1234.5},
-				thresholdExpressions: []string{"p(95)<2000"},
+				sink:                 &CounterSink{Value: 1234.5},
+				thresholdExpressions: []string{"count<2000"},
 				duration:             0,
 			},
 			want:    true,
@@ -666,8 +674,8 @@ func TestThresholdsRun(t *testing.T) {
 		{
 			name: "Running thresholds of existing sink but failing threshold",
 			args: args{
-				sink:                 DummySink{"p(95)": 3000},
-				thresholdExpressions: []string{"p(95)<2000"},
+				sink:                 &CounterSink{Value: 3000},
+				thresholdExpressions: []string{"count<2000"},
 				duration:             0,
 			},
 			want:    false,
@@ -676,7 +684,7 @@ func TestThresholdsRun(t *testing.T) {
 		{
 			name: "Running threshold on non existing sink does not fail",
 			args: args{
-				sink:                 DummySink{"dummy": 0},
+				sink:                 &CounterSink{},
 				thresholdExpressions: []string{"p(95)<2000"},
 				duration:             0,
 			},
@@ -686,7 +694,7 @@ func TestThresholdsRun(t *testing.T) {
 		{
 			name: "Running threshold on trend sink with no values and passing med statement succeeds",
 			args: args{
-				sink:                 &TrendSink{Values: []float64{}},
+				sink:                 getTrendSink(),
 				thresholdExpressions: []string{"med<39"},
 				duration:             0,
 			},
@@ -696,7 +704,7 @@ func TestThresholdsRun(t *testing.T) {
 		{
 			name: "Running threshold on trend sink with no values and non passing med statement fails",
 			args: args{
-				sink:                 &TrendSink{Values: []float64{}},
+				sink:                 getTrendSink(),
 				thresholdExpressions: []string{"med>39"},
 				duration:             0,
 			},
@@ -706,7 +714,7 @@ func TestThresholdsRun(t *testing.T) {
 		{
 			name: "Running threshold on trend sink with values and passing med statement succeeds",
 			args: args{
-				sink:                 &TrendSink{Values: []float64{70, 80, 90}, Count: 3},
+				sink:                 getTrendSink(70, 80, 90),
 				thresholdExpressions: []string{"med>39"},
 				duration:             0,
 			},
@@ -716,7 +724,7 @@ func TestThresholdsRun(t *testing.T) {
 		{
 			name: "Running threshold on trend sink with values and failing med statement fails",
 			args: args{
-				sink:                 &TrendSink{Values: []float64{70, 80, 90}, Count: 3},
+				sink:                 getTrendSink(70, 80, 90),
 				thresholdExpressions: []string{"med<39"},
 				duration:             0,
 			},