WordNet

set the speed, duration, or execution of; "we time the process to manufacture our cars very precisely"
a period of time considered as a resource under your control and sufficient to accomplish something; "take time to smell the roses"; "I didnt have time to finish"; "it took more than half my time"
a suitable moment; "it is time to go"
adjust so that a force is applied and an action occurs at the desired time; "The good player times his swing so as to hit the ball squarely"
an indefinite period (usually marked by specific attributes or activities); "he waited a long time"; "the time of year for planting"; "he was a great actor in his time"
regulate or set the time of; "time the clock"
the continuum of experience in which events pass from the future through the present to the past
an instance or single occasion for some event; "this time he succeeded"; "he called four times"; "he could do ten at a clip" (同)clip
a persons experience on a particular occasion; "he had a time holding back the tears"; "they had a good time together"
assign a time for an activity or event; "The candidate carefully timed his appearance at the disaster scene"
showing favoritism
being or affecting only a part; not total; "a partial description of the suspect"; "partial collapse"; "a partial eclipse"; "a partial monopoly"; "partial immunity"
shrub with terminal tufts of elongated leaves used locally for thatching and clothing; thick sweet roots are used as food; tropical southeastern Asia, Australia and Hawaii (同)Cordyline terminalis
the syllable naming the seventh (subtonic) note of any musical scale in solmization (同)te, si
the regulation of occurrence, pace, or coordination to achieve a desired effect (as in music, theater, athletics, mechanics)
the time when something happens
a more or less definite period of time now or previously present; "it was a sign of the times"

PrepTutorEJDIC

〈U〉《冠詞をつけずに》(空間に対しての)『時間』,時 / 〈U〉(時計で示される)『時刻』 / 〈U〉(ある方式で決められる)『時間』,標準時 / 〈C〉〈U〉(特定の)『時』,おり,ころ / 〈U〉《しばしば A ~》(ある長さの)『時間』,期間 / 〈U〉(要する)『時間』;暇 / 《しばしば複数形で》(歴史上の)『時代』 / 《複数形で》時勢,景気 / 《one's ~》(個人の)一生;若いころ;生涯の特定の時期 / 〈U〉《しばしば A ~》(ある経験をした)『時間』 / 〈C〉『…回』,度 / 〈C〉『…倍』 / …の時間を定める / (…に)…の調子を合わせる《+名+to+名》 / …の時間を計る
(また『part』)『一部分の』,部分的な;不完全な / 不公平な,偏った / 《補語にのみ用いて》(…が)特に好きで《+『to』+『名』》
シ(全音階の第7音)
時間の調節;時間を測定[記録]すること
…掛ける

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/05/07 22:23:02」(JST)

wiki en

[Wiki en表示]

The partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT or APTT) is a medical test that characterizes blood coagulation. A historic name for this measure is the Kaolin cephalin clotting time (KccT).^[1] Apart from detecting abnormalities in blood clotting,^[2] partial thromboplastin time is also used to monitor the treatment effects with heparin, a widely prescribed drug that reduces blood's tendency to clot. Partial thromboplastin time (PTT) measures the overall speed at which blood clots by means of two consecutive series of biochemical reactions known as the "intrinsic" (now referred to as the contact activation pathway) and common coagulation pathways. The partial thromboplastin time (PTT) is used in conjunction with another measure of how quickly blood clotting takes place called the prothrombin time (PT). The prothrombin time measures the speed of clotting by means of the extrinsic pathway (also known as the tissue factor pathway).

Methodology

Blue Top Vacutainer tube used for PT and PTT blood tests

Partial thromboplastin time is typically analyzed by a medical technologist or a laboratory technician on an automated instrument at 37 °C (as a nominal approximation of normal human body temperature). The test is termed "partial" due to the absence of tissue factor from the reaction mixture.

Blood is drawn into a test tube containing oxalate or citrate, molecules which act as an anticoagulant by binding the calcium in a sample. The blood is mixed, then centrifuged to separate blood cells from plasma (as Partial thromboplastin time is most commonly measured using blood plasma).
A sample of the plasma is extracted from the test tube and placed into a measuring test tube.
Next, an excess of calcium (in a phospholipid suspension) is mixed into the plasma sample (to reverse the anticoagulant effect of the oxalate enabling the blood to clot again).
Finally, in order to activate the intrinsic pathway of coagulation, an activator (such as silica, celite, kaolin, ellagic acid) is added, and the time the sample takes to clot is measured optically. Some laboratories use a mechanical measurement, which eliminates interferences from lipemic and icteric samples.

Interpretation

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:

use of heparin (or contamination of the sample)
antiphospholipid antibody (especially lupus anticoagulant, which paradoxically increases propensity to thrombosis)
coagulation factor deficiency (e.g. hemophilia)
Sepsis - coagulation factor consumption
Presence of antibodies against coagulation factors (factor inhibitors)

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 disappear 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.

‹ The template below (Bleeding worksheet) is being considered for deletion. See templates for discussion to help reach a consensus.›

Laboratory findings in various platelet and coagulation disorders (V - T)
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
Haemophilia	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

History

The aPTT was first described in 1953 by researchers at the University of North Carolina at Chapel Hill explaining the Carolina blue Vacutainer tube top color.^[4]

References

^ "KCCT - General Practice Notebook". GP Notebook. Oxbridge Solutions Ltd. Retrieved 2010-06-08.
^ "MedlinePlus Medical Encyclopedia: Partial thromboplastin time (PTT)". Retrieved 2009-01-01.
^ Korte, Wolfgang; Clarke, Susan; Lefkowitz, Jerry B. (January 2000). "Short activated partial thromboplastin times are related to increased thrombin generation and an increased risk for thromboembolism". American journal of clinical pathology 113 (1): 123–7. doi:10.1309/G98J-ANA9-RMNC-XLYU. PMID 10631865.
^ Langdell RD, Wagner RH, Brinkhous KM (1953). "Effect of antihemophilic factor on one-stage clotting tests; a presumptive test for hemophilia and a simple one-stage antihemophilic factor assy procedure". J. Lab. Clin. Med. 41 (4): 637–47. PMID 13045017.

UpToDate Contents

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Current therapy for blood vessel thrombosis has the risk of leading to gastrointestinal bleeding and thrombocytopenia. We previously reported that a new derivative of diosgenin, compound 5, had significant anti-inflammatory activity superior to that of aspirin, prolonged bleeding time, and inhibited
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Japanese Journal

「凝固・線溶系異常」を読む検査 : PT(prothrombin time、プロトロンビン時間) APTT(activated partial thromboplastin time、活性化部分トロンボプラスチン時間) (特集ズバッと読み取る! 検査値アセスメント検査値の"ここ見て!"9項目)

宮﨑あかり
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ABO Blood Type and Response of Activated Partial Thromboplastin Time to Dabigatran in Nonvalvular Atrial Fibrillation Patients

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新規血友病A 患者に対する第VIII因子製剤を用いた緊急対応 : 2 乳児例報告

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NAID 110009929979

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★リンクテーブル★

リンク元	「部分トロンボプラスチン時間」「PTT」
拡張検索	「activated partial thromboplastin time」「activated partial thromboplastin time assay」
関連記事	「time」「partial」「timing」「thromboplastin」