Factor XIII Deficiency Workup

Updated: Apr 02, 2018
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Perumal Thiagarajan, MD  more...
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Workup

Laboratory Studies

The following routine tests are the first step in the evaluation of any bleeding disorder:

  • Activated partial thromboplastin time (aPTT)
  • Prothrombin time (PT)
  • Thrombin-clottable fibrinogen level
  • Platelet count
  • Bleeding time (after ascertaining that the patient was not on antiplatelet drugs for at least the preceding 5 d)

However, these tests cannot be used to screen for FXIII deficiency because the results would be within reference ranges in a patient with isolated severe FXIII deficiency, [4] and blood collection, transport, and storage may alter results for these initial screening tests. [95]

The next test performed is a qualitative screening test for severe FXIII deficiency that assesses clot solubility in 5M urea or 1% monochloroacetic acid. If the thrombin and Ca2+ -induced clot lyses within a few hours, severe FXIII deficiency is suggested provided fibrinogen levels are qualitatively and quantitatively within reference range. Excluding hypofibrinogenemia and dysfibrinogenemia is important, since these conditions cause false-positive results on the 5M urea solubility test. The thrombin-clottable fibrinogen test can be used to exclude hypofibrinogenemia and dysfibrinogenemia.

If the 5M urea solubility test demonstrates positive results, this finding should be confirmed by quantitating FXIII activity using a monodansylcadaverine or putrescine incorporation assay, which must be performed by laboratory personnel with expertise.

Thromboelastography (TEG) is an old method used to assess clotting and lysis of fresh whole blood, and it has been used as an early tool in the initial evaluation, and as a simple laboratory test, of the mechanical strength (effect of FXIII) of fibrin sealants. [96] However, TEG cannot supplant any of the qualitative or quantitative tests discussed in this section.

A sensitive assay used to quantitate FXIII activity is based on monitoring the amount of ammonia (NH3) released by using glutamate dehydrogenase and nicotinamide adenine dinucleotide phosphate during the transamidation reaction (cross-linking) by FXIII. Note the following:

  • Reportedly, this test is sensitive over a wide range of activities, from a low of 1 U/L (0.1%) to a high of 470 U/L (47%), with an impressive coefficient of variation (CV) of less than 8%, even at very low FXIII activity levels. Note that a low CV in the low range of FXIII activity is a desirable feature of assays of this enzyme. [97]

  • Compared to the cumbersome conventional quantitative amine incorporation assays, the newer method appears to be simple, rapid, and reproducible not only in the assessment of inherited or acquired reductions of FXIII activity levels but also in the ability to measure increased FXIII activity levels resulting from certain mutations. The test fulfills the need for a simpler method to quantify FXIII activity.

  • The same group also has published results of a simple, quick (2 h), 1-step, enzyme-linked immunoassay (ELISA) to determine the presence of the plasma tetramer (A2 B2). Results demonstrated high sensitivity and low CVs within batches and in day-to-day variations. [98]

Another sensitive colorimetric assay based on incorporation of 5-(biotinamido) pentylamine into fibrin/fibrinogen was compared to a photometric method based on ammonia release and an ELISA of FXIII subunit A to quantitate FXIII activity. The test was shown to be sensitive to both reductions and increases in activity; the increases resulted from the FXIII Val34Leu mutation. [5]

In addition, a2 PI and plasminogen activator inhibitor-1 assays should be performed to exclude abnormalities in the fibrinolytic pathway, which accelerate clot lysis.

Sodium dodecylsulfate polyacrylamide gel electrophoresis under reducing conditions has been used to assess the presence of cross-linked g or a chains of fibrin, which is a reflection of FXIII activity. The studies must be performed by laboratory personnel with special expertise.

If the presence of an inhibitor is suspected in a patient with a positive urea solubility test result, the next step is to repeat the urea solubility test with mixtures containing varying proportions of patient and normal plasma to differentiate between a deficiency or an inhibitor as the cause of a positive result. Since FXIII activity is present in serum, serum also may be substituted for plasma in the test.

Semiquantitation of the susceptibility of the fibrin clot to fibrinolysis can be obtained by adding iodine-125-labeled fibrinogen, tissue plasminogen activator, thrombin, and Ca2+ to the patient's plasma, with measurement of the time to 50% clot lysis. This method is useful in evaluating inhibitors but must be performed by laboratory personnel with special expertise.

See Lorand for a recent review of further details of the sequence of necessary testing to confirm the presence of a FXIII inhibitor. [88]

Acquired systemic disorders, including decompensated DIC and liver disease, require standard tests to confirm the diagnosis.

Caution is warranted in obtaining blood samples for any coagulation assays from heparinized central lines because of the effect of large amounts of heparin on any coagulation test that depends on thrombin generation.

Prenatal diagnosis is as follows:

  • Use of several diagnostic procedures has been well established in the evaluation of patients with FVIII and factor IX (FIX) deficiencies. In one case report, a short tandem repeat marker that was closely linked to subunit A was used antenatally to identify the presence of a severe bleeding disorder in a subsequent pregnancy in a family in which an older sibling had severe FXIII deficiency. [99]

  • Chorionic villous sampling at approximately 10-12 weeks of gestation or amniocentesis at 16-20 weeks of gestation can be performed to obtain fetal cells for DNA analysis or for linkage studies. If DNA analysis cannot be performed, fetal blood obtained by fetoscopy at approximately 20 weeks of gestation can be used. In general, these procedures carry risks ranging from a low of approximately 0.5% maternal-fetal complications to a high of approximately 1-6% fetal death for fetoscopy.

  • Perform these procedures only after intense genetic and obstetric counseling of the parents.

Perform liver function tests; kidney function tests; HIV-1 and HIV-2 antigen and antibody tests; hepatitis A (HAV), hepatitis B (HBV), hepatitis C (HCV), hepatitis D, and hepatitis E antigen/antibody levels; and other tests as needed.

Assess a-fetoprotein levels and other tumor markers as needed in patients with chronic hepatitis.

FXIII, which is involved in wound healing and angiogenesis, may be detectable by highly sensitive chemiluminescent ELISAs in tiny volumes of tear. This concept may provide a tool for monitoring FXIII subunit and complex levels in pathological conditions. [100]

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Imaging Studies

MRI, CT scan, and ultrasound have been used to localize, quantify, and serially monitor the location and response of bleeding to specific therapy. Perform other imaging tests as needed to diagnose associated diseases.

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Other Tests

Perform ECGs as needed.

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Procedures

Diagnostic amniocentesis, chorionic villous sampling, or fetoscopy may be performed during pregnancy. Perform other routine procedures when indicated. Perform arthrocentesis only when infection is suggested. Any invasive procedure requires the appropriate factor replacement.

When indicated, perform other procedures, such as colonoscopy, in persons without hemophilia. Evaluate persistent GI tract bleeding without an apparent cause using endoscopy and colonoscopy to exclude underlying lesions. Persistent genitourinary tract bleeding requires evaluation for nephrolithiasis, tumors, or obstruction. If a biopsy is needed, patients require replacement therapy prior to and following the procedure until the biopsy site has healed.

Invasive lifesaving procedures should be performed in patients with inhibitors only in concert with appropriate treatment.

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