 	gauge : (key, value, sampleRate = 1)->
 		statsd.gauge buildKey(key), value, sampleRate
 		key = Metrics.buildPromKey(key)
-		if !promMetrics[key]
+		if !promMetrics[key]?
 			promMetrics[key] = new prom.Gauge({
 				name: key,
 				help: key, 

	globalGauge: (key, value, sampleRate = 1)->
		statsd.gauge buildGlobalKey(key), value, sampleRate
		key = Metrics.buildPromKey(key)
		if !promMetrics[key]
			promMetrics[key] = new prom.Gauge({
				name: key,
				help: key, 

	timing: (key, timeSpan, sampleRate)->
		statsd.timing(buildKey(key), timeSpan, sampleRate)
		key = Metrics.buildPromKey("timer_#{key}")
		if !promMetrics[key]?
			promMetrics[key] = new prom.Summary({
				name: key,
				help: key,
