Summary
An unusual bleeding disorder clinically resembling factor XIII deficiency is presented.
The only detectable coagulation abnormality was rapid clot dissolution in 1% monochloroacetic
acid. This abnormality was ascribed to the sustained increase of a pepsin-like plasma
protease which is activated at low pH. A systematic search for similar phenomena revealed
that massive blood transfusion may also enhance plasma-clot solubility in acid, possibly
by release of a red cell protease. We conclude that the acid clot solubility test
is not a specific indicator of factor XIII deficiency, but this simple assay is recommended
for further studies of acid plasma protease activity. The diagnostic relevance and
pathophysiologic importance of increased pepsin-like activity in plasma remain to
be elucidated.
