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Abdul Mannan: Why Quantitative FXIII Testing Matters

Abdul Mannan/LinkedIn

Jul 27, 2026, 12:24

Abdul Mannan: Why Quantitative FXIII Testing Matters

Abdul Mannan, Consultant Haematologist at Betsi Cadwaladr University Health Board, shared a post on LinkedIn:

“Your patient bled abnormally.

PT, APTT, and platelets all came back normal.

Coag screen closed the case?

Not so fast.

A 2010 UCL and Great Ormond Street paper makes an uncomfortable point: the clot solubility test, still the most widely used FXIII screen, only detects activity below 1 to 5 percent.

It misses mild, moderate, heterozygous, and acquired deficiency entirely.

Here’s what matters:

Acquired FXIII deficiency is common, not rare. 21 percent of general hospital inpatients and 52 percent of paediatric ICU patients fall below the normal range.
PT, APTT, and TT stay normal in FXIII deficiency. You have to actively think to request it.
The fix is a quantitative chromogenic (ammonia release) assay, not clot solubility. CV of 2 to 4 percent, and it covers the full range rather than just the severe end.
In high-risk surgical cancer patients, FXIII substitution reduced blood loss by 29 percent (Korte et al, 2009).

I have seen patients with unexplained bleeding and a ‘normal’ coag screen who were never tested for this.

If your lab is only running clot solubility, it is only catching the tip of the iceberg.

Does your lab offer quantitative FXIII activity, or only clot solubility?”

Abdul Mannan: Why Quantitative FXIII Testing Matters