針對PT延長aPTT正常的纖維蛋白原缺乏病患之診斷建議

Recommendation for the diagnosis of fibrinogen deficiency patient with prolonged PT/normal aPTT

日前本實驗室接獲一病患，其檢驗結果為PT延長、aPTT正常，初步推斷是缺乏第七凝固因子，然而病患第七因子活性檢驗結果為正常，與臨床推測不相符。故實驗室進一步分析病患的纖維蛋白原，發現其纖維蛋白原<30mg/dL，為嚴重缺乏，最終協助臨床診斷出病患為先天性纖維蛋白原缺乏症。藉此案例延伸，本研究目的為：1.探討缺乏纖維蛋白原對PT、aPTT的影響。2.進行不同纖維蛋白原檢驗方法的比較，包含(1) Clauss凝固法及(2) PT-derived fibrinogen換算法。
結果顯示PT、aPTT檢驗約有兩成機率無法反應出相對應的纖維蛋白原嚴重缺乏，建議臨床醫師應善加利用纖維蛋白原檢驗工具。而PT-derived fibrinogen方法學雖方便快速，但其結果在低濃度範圍不穩定，因此建議只用於快速篩查或常規監測情況下的替代方法，對於低值的病患，仍建議以Clauss凝固法檢測，才能獲得準確的報告。

A few days ago, our laboratory received a case. The test results showed: PT was prolonged, and aPTT was normal, so the preliminary inference was the lack of coagulation factor VII. However, the test result of factor VII activity of the patient was normal, which was inconsistent with the clinical speculation. Therefore, the laboratory further analyzed the patient’s fibrinogen and found that the fibrinogen < 30mg/dL was severely deficient, and finally assisted in the clinical diagnosis of the patient’s congenital fibrinogen deficiency. Extending this case, the purpose of this study is: 1. To explore the impact of lack of fibrinogen on PT and aPTT. 2. To compare different fibrinogen test methods, including (1) Clauss coagulation method and (2) PT-derived fibrinogen conversion method.
The results showed that about 20% of the PT and aPTT tests could not reflect the corresponding severe deficiency of fibrinogen. It is recommended that clinicians should make good use of fibrinogen test tools. Although the PT-derived fibrinogen method is convenient and fast, its results are unstable in the low concentration range, so it is recommended to be used only as an alternative method in the case of rapid screening or routine monitoring. For patients with low values, Clauss coagulation is still recommended In order to obtain accurate reports.