活性化部分トロンボプラスチン時間 activated partial thromboplastin time
出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2014/01/04 12:56:38」(JST)
活性化部分トロンボプラスチン時間(かっせいか・ぶぶん・トロンボプラスチン・じかん)とは、血液凝固能検査のひとつ。APTT(activated partial thromboplastin time)とも略される。内因系及び共通系の凝固異常を判定する検査として用いられる。
まず、被検者の静脈血を採取する。このうち血漿に部分トロンボプラスチン、カルシウムの他、カオリン、セライトまたはエラジン酸などの接触因子活性化物質を添加し、凝固時間を測定する。PTT(部分トロンボプラスチン時間)に比べ、より安定した結果を得られる。[1]
正常ではAPTT (試薬がリン脂質+カルシウム+エラジン酸) 30-45秒。
APTTに関与する因子は、プレカリクレイン・HMW-キニノゲン・第XII因子・第XI因子・第IX因子・第VIII因子・第V因子・第II因子およびフィブリノーゲンである。
血友病は内因系の第VIII因子や第IX因子に異常がある。そのためAPTTは延長するものの、プロトロンビン時間(PT)は延長しない。
同様に第Ⅷ因子に異常があるヴォン・ヴィレブランド病もAPTT延長・PT正常を示す。
[ヘルプ] |
この項目は、医学に関連した書きかけの項目です。この項目を加筆・訂正などしてくださる協力者を求めています(プロジェクト:医学/Portal:医学と医療)。 |
Partial thromboplastin time | |
---|---|
Intervention | |
MeSH | D010314 |
The partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT or APTT) is a performance indicator measuring the efficacy of both the "intrinsic" (now referred to as the contact activation pathway) and the common coagulation pathways. Apart from detecting abnormalities in blood clotting,[1] it is also used to monitor the treatment effects with heparin, a major anticoagulant. It is used in conjunction with the prothrombin time (PT) which measures the extrinsic pathway. Kaolin cephalin clotting time (KccT) is a historic name for the activated partial thromboplastin time.[2]
Blood samples are collected in tubes with oxalate or citrate to arrest coagulation by binding calcium. The specimen is then delivered to the laboratory. In order to activate the intrinsic pathway, phospholipid, an activator (such as silica, celite, kaolin, ellagic acid), and calcium (to reverse the anticoagulant effect of the oxalate) are mixed into the plasma sample. The time is measured until a thrombus (clot) forms. This testing is performed by a medical technologist.
The test is termed "partial" due to the absence of tissue factor from the reaction mixture.
The typical reference range is between 30 seconds and 50 s (depending on laboratory). Shortening of the PTT is considered to have little clinical relevance, but some research indicates that it might increase risk of thromboembolism.[3] Normal PTT times require the presence of the following coagulation factors: I, II, V, VIII, IX, X, XI, & XII. Notably, deficiencies in factors VII or XIII will not be detected with the PTT test. Prolonged APTT may indicate:
To distinguish the above causes, mixing tests are performed, in which the patient's plasma is mixed (initially at a 50:50 dilution) with normal plasma. If the abnormality does not disappear, the sample is said to contain an "inhibitor" (either heparin, antiphospholipid antibodies or coagulation factor specific inhibitors), while if it does correct a factor deficiency is more likely. Deficiencies of factors VIII, IX, XI and XII and rarely von Willebrand factor (if causing a low factor VIII level) may lead to a prolonged aPTT correcting on mixing studies.
Condition | Prothrombin time | Partial thromboplastin time | Bleeding time | Platelet count |
---|---|---|---|---|
Vitamin K deficiency or warfarin | Prolonged | Normal or mildly prolonged | Unaffected | Unaffected |
Disseminated intravascular coagulation | Prolonged | Prolonged | Prolonged | Decreased |
Von Willebrand disease | Unaffected | Prolonged or unaffected | Prolonged | Unaffected |
Hemophilia | Unaffected | Prolonged | Unaffected | Unaffected |
Aspirin | Unaffected | Unaffected | Prolonged | Unaffected |
Thrombocytopenia | Unaffected | Unaffected | Prolonged | Decreased |
Liver failure, early | Prolonged | Unaffected | Unaffected | Unaffected |
Liver failure, end-stage | Prolonged | Prolonged | Prolonged | Decreased |
Uremia | Unaffected | Unaffected | Prolonged | Unaffected |
Congenital afibrinogenemia | Prolonged | Prolonged | Prolonged | Unaffected |
Factor V deficiency | Prolonged | Prolonged | Unaffected | Unaffected |
Factor X deficiency as seen in amyloid purpura | Prolonged | Prolonged | Unaffected | Unaffected |
Glanzmann's thrombasthenia | Unaffected | Unaffected | Prolonged | Unaffected |
Bernard-Soulier syndrome | Unaffected | Unaffected | Prolonged | Decreased or unaffected |
Factor XII deficiency | Unaffected | Prolonged | Unaffected | Unaffected |
C1INH deficiency | Unaffected | Shortened | Unaffected | Unaffected |
The aPTT was first described in 1953 by researchers at the University of North Carolina at Chapel Hill.[4]
|
全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.
国試過去問 | 「109I056」「103D055」「105I002」「111I008」「101F042」 |
リンク元 | 「急性心筋梗塞」「抗リン脂質抗体症候群」「プロトロンビン時間」「部分トロンボプラスチン時間」「プロトロンビン」 |
関連記事 | 「AP」「aPTT」 |
C
※国試ナビ4※ [109I055]←[国試_109]→[109I057]
C
※国試ナビ4※ [103D054]←[国試_103]→[103D056]
C
※国試ナビ4※ [105I001]←[国試_105]→[105I003]
D
※国試ナビ4※ [111I007]←[国試_111]→[111I009]
D
※国試ナビ4※ [101F041]←[国試_101]→[101F043]
特徴的な疼痛 | 持続性で、ひどい痛み、典型的には胸骨下痛 |
交感神経による作用 | 発汗 |
皮膚が湿って冷たく感じられる | |
副交感神経による作用 | 悪心・嘔吐 |
倦怠感 | |
炎症反応 | 中程度の発熱 |
心臓の所見 | IV音ギャロップ(うっ血性心不全があればIII音も) |
その他 | 運動異常を伴う膨隆(前壁梗塞なら) |
心膜摩擦音(心膜炎があれば) | |
収縮期雑音(僧帽弁閉鎖不全症や心室中隔欠損があれば) | |
肺のラ音(うっ血性心不全があれば) | |
頚動脈の拡大(右室梗塞) |
上昇 | 正常化 | |
ミオグロビン | 1-2時間 | 2-3日 |
H-FABP | 1-2時間 | 24時間 |
WBC | 2-3時間 | 7日 |
CK-MB | 3-4時間 | 3-7日 |
トロポニンT | 3-4時間 | 14-21日 |
心筋ミオシン軽鎖I | 4-6時間 | 7-14日 |
AST | 6-12時間 | 3-7日 |
LDH1,2 | 12-24時間 | 8-14日 |
CRP | 1-3日 | 21日 |
→→→→→→→→→→→→→→→→→→ | ||||||
myo | W | TnT | myo | AST | LDH | CRP |
H | CK | |||||
2-3時間 ~~~~~~半日~ 1日 |
皮膚 | 網状皮斑、浅在性血栓性静脈炎、爪下線状出血、足潰瘍、皮膚遠位部虚血、皮膚梗塞、blue-toe syndrome |
神経系 | 一過性脳虚血、脳卒中、多発梗塞性認知症、舞踏病、横断性脊髄炎、脳症、片頭痛、pseudotumor cerebri、脳静脈血栓 |
心臓 | 狭心症、心筋梗塞、冠状動脈症、心弁膜症疣贅、心臓内血栓 |
肺 | 肺塞栓、肺高血圧 |
血液 | 血小板減少、溶血性貧血 |
消化器 | Budd-Chiari syndrome、肝梗塞 |
腎臓 | 糸球体血栓、腎不全、高血圧の亢進、腎動脈血栓、腎静脈血栓 |
産科系 | 胎児喪失、子宮内胎児発育遅延、HELLP症候群、羊水過少 |
眼科 | 網膜静脈閉塞、網膜動脈閉塞、血管閉塞性網膜症、虚血性視神経症 |
内分泌 | 副腎不全 |
筋骨格系 | 阻血性壊死(?) |
.