<s>[INST] context: Bleeding from umbilical stump suggests Factor XIII deficiency.
Neonates with a positive bleeding history, particularly with features such as delayed bleeding, umbilical stump bleeding or miscarriages and in whom the initial panel of screening test is negative should be tested for factor XIII deficiency.
The normal screening tests such as PT and PTT are normal in factor XIII deficiency because factor XIII is needed to stabilize the clot after a fibrin clot has formed, so tests used for evaluating the extrinsic or intrinsic pathways are not affected. (Note, that factor XIII is used, once the clot has formed.)

Test used for evaluation of factor XIII

Test used in qualitative evaluation of factor XIII is evaluation of clot stability in 5M urea.
Clots formed from normal individuals remain stable in 5M urea, while clots from factor XIII deficient patient dissolve in urea.
This assay detects only the most severely affected patients with 1% to 2% factor XIII deficieincy or tests.
A quantitative chromogenic assay has been developed but is not yet readily available.
In addition to hemorrhages these patients may have poor wound healing a high incidence of infertility among males and abortion among affected females and a high incidence of intracerebral hemorrhage. [/INST] question: A newborn baby presented with profuse bleeding from umbilical stump after birth. Probable diagnosis is – | options: A: Factor XIII deficiency B: VWF deficiency C: Factor XII deficiency D: Glanzmann thrombosthenia | answer: A </s>