洗替結果(=araigae) is, in a broad sense, construed as “the result of inventory valuation.”

In a narrower sense, however,
the term “洗替” refers to a specific way of asset (inventory) evaluation (ergo, further context needed!).

As one of the methods of LCM (Lower of Cost or Market ), “洗替”method allows you, in every accounting period, to choose the lower cost of the following two: the historical cost (purchasing price) of assets and their current replacement cost (market price). Other option is to compare the cost already booked in the preceding period and the market price.

My suggestion for “洗替” in a specific and technical sense is: historical cost based LCM.

Let me recommend you to take a brief look at the following sites for LCM (低価法), which are very helpful.

http://www2g.biglobe.ne.jp/‾ykawamur/gaap040.htm
http://taxguide.completetax.com/text/c60s15d155.asp