Cumulative Official WHO Updates to ICD 10 - 1996 - 2001

If no condition is found that can cause the direct cause of death, there is no sequence ending with the direct cause of death. ... subcategories at B20-B23 are the only optional four-character codes for countries using the four-character version of ICD-10. These four-character subcategories are provided for use where it is not possible or not ... ................
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