diff --git a/langchain/vectorstores/base.py b/langchain/vectorstores/base.py
index d529e253abf..a09ee25759c 100644
--- a/langchain/vectorstores/base.py
+++ b/langchain/vectorstores/base.py
@@ -234,6 +234,8 @@ class VectorStore(ABC):
         Returns:
             List of Tuples of (doc, similarity_score)
         """
+        score_threshold = kwargs.pop("score_threshold", None)
+
         docs_and_similarities = self._similarity_search_with_relevance_scores(
             query, k=k, **kwargs
         )
@@ -246,7 +248,6 @@ class VectorStore(ABC):
                 f" 0 and 1, got {docs_and_similarities}"
             )
 
-        score_threshold = kwargs.get("score_threshold")
         if score_threshold is not None:
             docs_and_similarities = [
                 (doc, similarity)
diff --git a/langchain/vectorstores/pgvector.py b/langchain/vectorstores/pgvector.py
index b0958b78fa5..a2969b9fa0f 100644
--- a/langchain/vectorstores/pgvector.py
+++ b/langchain/vectorstores/pgvector.py
@@ -593,15 +593,15 @@ class PGVector(VectorStore):
 
         # Default strategy is to rely on distance strategy provided
         # in vectorstore constructor
-        if self.distance_strategy == DistanceStrategy.COSINE:
+        if self._distance_strategy == DistanceStrategy.COSINE:
             return self._cosine_relevance_score_fn
-        elif self.distance_strategy == DistanceStrategy.EUCLIDEAN:
+        elif self._distance_strategy == DistanceStrategy.EUCLIDEAN:
             return self._euclidean_relevance_score_fn
-        elif self.distance_strategy == DistanceStrategy.MAX_INNER_PRODUCT:
+        elif self._distance_strategy == DistanceStrategy.MAX_INNER_PRODUCT:
             return self._max_inner_product_relevance_score_fn
         else:
             raise ValueError(
                 "No supported normalization function"
-                f" for distance_strategy of {self.distance_strategy}."
+                f" for distance_strategy of {self._distance_strategy}."
                 "Consider providing relevance_score_fn to PGVector constructor."
             )