diff --git a/ext/ddtrace_profiling_native_extension/collectors_cpu_and_wall_time.c b/ext/ddtrace_profiling_native_extension/collectors_cpu_and_wall_time.c
index 179391c950a..4d738df306d 100644
--- a/ext/ddtrace_profiling_native_extension/collectors_cpu_and_wall_time.c
+++ b/ext/ddtrace_profiling_native_extension/collectors_cpu_and_wall_time.c
@@ -128,9 +128,8 @@ struct trace_identifiers {
 
   bool valid;
   ddog_CharSlice local_root_span_id;
-  ddog_CharSlice span_id;
+  uint64_t span_id;
   char local_root_span_id_buffer[MAXIMUM_LENGTH_64_BIT_IDENTIFIER];
-  char span_id_buffer[MAXIMUM_LENGTH_64_BIT_IDENTIFIER];
   VALUE trace_endpoint;
 };
 
@@ -583,7 +582,7 @@ static void trigger_sample_for_thread(
 
   if (trace_identifiers_result.valid) {
     labels[label_pos++] = (ddog_Label) {.key = DDOG_CHARSLICE_C("local root span id"), .str = trace_identifiers_result.local_root_span_id};
-    labels[label_pos++] = (ddog_Label) {.key = DDOG_CHARSLICE_C("span id"), .str = trace_identifiers_result.span_id};
+    labels[label_pos++] = (ddog_Label) {.key = DDOG_CHARSLICE_C("span id"), .num = trace_identifiers_result.span_id};
 
     if (trace_identifiers_result.trace_endpoint != Qnil) {
       // The endpoint gets recorded in a different way because it is mutable in the tracer and can change during a
@@ -870,19 +869,13 @@ static void trace_identifiers_for(struct cpu_and_wall_time_collector_state *stat
   if (numeric_local_root_span_id == Qnil || numeric_span_id == Qnil) return;
 
   unsigned long long local_root_span_id = NUM2ULL(numeric_local_root_span_id);
-  unsigned long long span_id = NUM2ULL(numeric_span_id);
-
   snprintf(trace_identifiers_result->local_root_span_id_buffer, MAXIMUM_LENGTH_64_BIT_IDENTIFIER, "%llu", local_root_span_id);
-  snprintf(trace_identifiers_result->span_id_buffer, MAXIMUM_LENGTH_64_BIT_IDENTIFIER, "%llu", span_id);
 
   trace_identifiers_result->local_root_span_id = (ddog_CharSlice) {
     .ptr = trace_identifiers_result->local_root_span_id_buffer,
     .len = strlen(trace_identifiers_result->local_root_span_id_buffer)
   };
-  trace_identifiers_result->span_id = (ddog_CharSlice) {
-    .ptr = trace_identifiers_result->span_id_buffer,
-    .len = strlen(trace_identifiers_result->span_id_buffer)
-  };
+  trace_identifiers_result->span_id = NUM2ULL(numeric_span_id);
 
   trace_identifiers_result->valid = true;
 
diff --git a/spec/datadog/profiling/collectors/cpu_and_wall_time_spec.rb b/spec/datadog/profiling/collectors/cpu_and_wall_time_spec.rb
index e3d56dd376a..6885ebe22ab 100644
--- a/spec/datadog/profiling/collectors/cpu_and_wall_time_spec.rb
+++ b/spec/datadog/profiling/collectors/cpu_and_wall_time_spec.rb
@@ -357,7 +357,7 @@ def stats
 
             expect(t1_sample.fetch(:labels)).to include(
               :'local root span id' => @t1_local_root_span_id.to_s,
-              :'span id' => @t1_span_id.to_s,
+              :'span id' => @t1_span_id.to_i,
             )
           end
 
diff --git a/spec/datadog/profiling/spec_helper.rb b/spec/datadog/profiling/spec_helper.rb
index 71dd0856111..8b24c5ad19e 100644
--- a/spec/datadog/profiling/spec_helper.rb
+++ b/spec/datadog/profiling/spec_helper.rb
@@ -65,7 +65,7 @@ def samples_from_pprof(pprof_data)
         labels: sample.label.map do |it|
           [
             string_table[it.key].to_sym,
-            it.num == 0 ? string_table[it.str] : raise('Unexpected: label encoded as number instead of string'),
+            it.num == 0 ? string_table[it.str] : it.num,
           ]
         end.to_h,
       }