diff --git a/tests/src/psa_crypto_helpers.c b/tests/src/psa_crypto_helpers.c
index d59a8f8..e1ea2b5 100644
--- a/tests/src/psa_crypto_helpers.c
+++ b/tests/src/psa_crypto_helpers.c
@@ -70,9 +70,20 @@
 
     mbedtls_psa_get_stats(&stats);
 
+#if defined(MBEDTLS_CTR_DRBG_C) && !defined(MBEDTLS_AES_C) && \
+    !defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
+    /* When AES_C is not defined and PSA does not have an external RNG,
+     * then CTR_DRBG uses PSA to perform AES-ECB. In this scenario 1 key
+     * slot is used internally from PSA to hold the AES key and it should
+     * not be taken into account when evaluating remaining open slots. */
+    if (stats.volatile_slots > 1) {
+        return "A volatile slot has not been closed properly.";
+    }
+#else
     if (stats.volatile_slots != 0) {
         return "A volatile slot has not been closed properly.";
     }
+#endif
     if (stats.persistent_slots != 0) {
         return "A persistent slot has not been closed properly.";
     }