diff --git a/genotype_api/dto/sample.py b/genotype_api/dto/sample.py
index 8001bbd..0b2d2ea 100644
--- a/genotype_api/dto/sample.py
+++ b/genotype_api/dto/sample.py
@@ -25,10 +25,9 @@ class SampleResponse(BaseModel):
     sex: Sexes | None = None
     created_at: datetime | None = datetime.now()
     analyses: list[AnalysisOnSample] | None = None
-    detail: SampleDetail | None
+    detail: SampleDetail = None
 
     @field_validator("detail")
-    @classmethod
     def get_detail(cls, value, values) -> SampleDetail | None:
         analyses = values.get("analyses")
         if analyses: