Hello, I am fairly new to the special coagulation field and am interested in finding out how most labs set up contact factor assays. What do you use for calibrators and controls for high molecular weight kininogen (HMWK) and prekallikrein (PK). Looking forward to your insight and I really enjoy the Fritsma Factor! Mary Block, Cincinnati Children’s Hospital
Hello, Mary, and welcome to Fritsma Factor. You may have relatively few opportunities to assay HMWK, (Fitzgerald factor), or PK (Fletcher factor), as deficiencies are rare and have no clinical consequence. Factor XII deficiency is comparatively common, however there is no association with bleeding, though you may run a few factor XII assays in follow-up to an unexplained prolonged partial thromboplastin time PTT in non-bleeding patients. To set up the assays, you can obtain PK and factor XII-deficient plasmas from plasma distributors such as Precision BioLogic; HMWK-deficient plasma may be more difficult to locate. Precision also offers calibrators and controls for PK and factor XII assays.The assays are set up just as you would a factor VIII or IX assay, simply substituting the respective factor-deficient plasma. Specialty laboratories such asEsoterix offer HMWK assays, but I recommend you phone first to ensure the assay is available. I hope this helps. Geo
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