diff --git a/lib/includes/spdylay/spdylay.h b/lib/includes/spdylay/spdylay.h
index f100343..c0444be 100644
--- a/lib/includes/spdylay/spdylay.h
+++ b/lib/includes/spdylay/spdylay.h
@@ -415,17 +415,6 @@ typedef enum {
   SPDYLAY_GOAWAY_INTERNAL_ERROR = 11
 } spdylay_goaway_status_code;
 
-/**
- * @macro
- * Lowest priority value in SPDY/2, which is 3.
- */
-#define SPDYLAY_SPDY2_PRI_LOWEST 3
-/**
- * @macro
- * Lowest priority value in SPDY/3, which is 7.
- */
-#define SPDYLAY_SPDY3_PRI_LOWEST 7
-
 /**
  * @struct
  * The control frame header.
@@ -468,10 +457,9 @@ typedef struct {
    */
   int32_t assoc_stream_id;
   /**
-   * The priority of this frame. 0 (Highest) to
-   * :macro:`SPDYLAY_SPDY2_PRI_LOWEST` or
-   * :macro:`SPDYLAY_SPDY3_PRI_LOWEST` (lowest), depending on the
-   * protocol version.
+   * The priority of this frame. 0 is the highest priority value. Use
+   * `spdylay_session_get_pri_lowest()` to know the lowest priority
+   * value.
    */
   uint8_t pri;
   /**
@@ -1240,6 +1228,13 @@ void* spdylay_session_get_stream_user_data(spdylay_session *session,
  */
 size_t spdylay_session_get_outbound_queue_size(spdylay_session *session);
 
+/**
+ * @function
+ *
+ * Returns lowest priority value for the |session|.
+ */
+uint8_t spdylay_session_get_pri_lowest(spdylay_session *session);
+
 /**
  * @function
  *
@@ -1247,11 +1242,8 @@ size_t spdylay_session_get_outbound_queue_size(spdylay_session *session);
  * frames.
  *
  * The |pri| is priority of this request. 0 is the highest priority
- * value.  If the |session| is initialized with the version
- * :macro:`SPDYLAY_PROTO_SPDY2`, the lowest priority value is
- * :macro:`SPDYLAY_SPDY2_PRI_LOWEST`.  If the |session| is initialized
- * with the version :macro:`SPDYLAY_PROTO_SPDY3`, the lowest priority
- * value is :macro:`SPDYLAY_SPDY3_PRI_LOWEST`.
+ * value. Use `spdylay_session_get_pri_lowest()` to know the lowest
+ * priority value for this |session|.
  *
  * The |nv| contains the name/value pairs. For i > 0, ``nv[2*i]``
  * contains a pointer to the name string and ``nv[2*i+1]`` contains a
@@ -1372,13 +1364,10 @@ int spdylay_submit_response(spdylay_session *session,
  *
  * The |assoc_stream_id| is used for server-push. If |session| is
  * initialized for client use, |assoc_stream_id| is ignored.
-
+ *
  * The |pri| is priority of this request. 0 is the highest priority
- * value.  If the |session| is initialized with the version
- * :macro:`SPDYLAY_PROTO_SPDY2`, the lowest priority value is
- * :macro:`SPDYLAY_SPDY2_PRI_LOWEST`.  If the |session| is initialized
- * with the version :macro:`SPDYLAY_PROTO_SPDY3`, the lowest priority
- * value is :macro:`SPDYLAY_SPDY3_PRI_LOWEST`.
+ * value. Use `spdylay_session_get_pri_lowest()` to know the lowest
+ * priority value for this |session|.
  *
  * The |nv| contains the name/value pairs. For i > 0, ``nv[2*i]``
  * contains a pointer to the name string and ``nv[2*i+1]`` contains a
diff --git a/lib/spdylay_session.c b/lib/spdylay_session.c
index f464028..6c2c207 100644
--- a/lib/spdylay_session.c
+++ b/lib/spdylay_session.c
@@ -2322,9 +2322,9 @@ int spdylay_session_resume_data(spdylay_session *session, int32_t stream_id)
 uint8_t spdylay_session_get_pri_lowest(spdylay_session *session)
 {
   if(session->version == SPDYLAY_PROTO_SPDY2) {
-    return SPDYLAY_SPDY2_PRI_LOWEST;
+    return SPDYLAY_PRI_LOWEST_SPDY2;
   } else if(session->version == SPDYLAY_PROTO_SPDY3) {
-    return SPDYLAY_SPDY3_PRI_LOWEST;
+    return SPDYLAY_PRI_LOWEST_SPDY3;
   } else {
     return 0;
   }
diff --git a/lib/spdylay_session.h b/lib/spdylay_session.h
index c1408e1..589e689 100644
--- a/lib/spdylay_session.h
+++ b/lib/spdylay_session.h
@@ -38,6 +38,17 @@
 #include "spdylay_buffer.h"
 #include "spdylay_outbound_item.h"
 
+/**
+ * @macro
+ * Lowest priority value in SPDY/2, which is 3.
+ */
+#define SPDYLAY_PRI_LOWEST_SPDY2 3
+/**
+ * @macro
+ * Lowest priority value in SPDY/3, which is 7.
+ */
+#define SPDYLAY_PRI_LOWEST_SPDY3 7
+
 typedef struct {
   spdylay_outbound_item *item;
   /* Buffer for outbound frames. Used to pack one frame. The memory
@@ -472,11 +483,6 @@ spdylay_outbound_item* spdylay_session_pop_next_ob_item
 spdylay_outbound_item* spdylay_session_get_next_ob_item
 (spdylay_session *session);
 
-/*
- * Returns lowest priority value.
- */
-uint8_t spdylay_session_get_pri_lowest(spdylay_session *session);
-
 /*
  * Updates local settings with the |iv|. The number of elements in the
  * array pointed by the |iv| is given by the |niv|.  This function