Blood activated partial thromboplastin time

Before administering the first dose of heparin, the nurse obtains the patients vital signs. The most commonly used test to monitor heparin is activated partial thromboplastin time (APTT). Blood is drawn for laboratory studies before giving the first dose of heparin to obtain baseline data (See the discussion on preadministration assessment for the oral anticoagulants.)... 

Check complete blood count, prothrombin time, international normalization ratio, activated partial thromboplastin time, fibrinogen levels... 

Baseline complete blood count (CBC) and coagulation tests (activated partial thromboplastin time and International Normalized Ratio) should be obtained, as most patients will receive antithrombotic therapy, which increases the risk for bleeding. 

ACE, angiotensin-converting enzyme aPTT, activated partial thromboplastin time ARB, angiotensin receptor blocker BP, blood pressure CBC, complete blood count ECC, electrocardiogram HR, heart rate INR, International Normalized Ratio RR, respiratory rate SCr, serum creatinine, TTP, thrombotic thrombocytopenic purpura. 

Activated partial thromboplastin time aPTT is performed by adding calcium phospholipids and kaolin to citrated blood and measures the time required for a fibrin clot to form. In this manner, aPTT measures the activity of intrinsic and common pathways. Prolongation of aPTT may be due to a deficiency or inhibitor for factors II, V, VIII, IX, X, XI, and XII. It also may be due to heparin, direct thrombin inhibitors, vitamin K deficiency, liver disease, or lupus anticoagulant. 

Baseline laboratory tests should include complete blood cell count, prothrombin time, activated partial thromboplastin time, liver and renal function tests, and serum carcinoembryonic antigen (CEA). Serum CEA can serve as a marker for monitoring colorectal cancer response to treatment, but it is too insensitive and nonspecific to be used as a screening test for early-stage colorectal cancer. 

Therapy with heparin occurs in an inpatient setting. Heparin inhibits both in vitro and in vivo clotting of blood. Whole blood clotting time and activated partial thromboplastin time (aPTT) are prolonged in proportion to blood heparin concentrations. 

BP, blood pressure INR, international normalized ratio APTT, activated partial thromboplastin time ... 

Treatment options are largely supportive. An assessment should first be made for airway patency and adequacy of breathing. Circulation may become affected as shock develops secondary to severe gastroenteritis. The following laboratory studies are recommended for all symptomatic patients computerized blood count, electrolytes, and coagulation studies (prothrobin time, activated partial thromboplastin time). In cases of uncertain or unknown exposure, there is an enzyme-linked immunosorption assay test available for the detection and verification of the presence of ricin... 

Key TPA, tissue plasminogen activator ASA, aspirin PT, prothrombin time APTT, activated partial thromboplastin time INR, international normalized ratio CBC, complete blood count IVIG, intravenous immune globulin SAH, subarachnoid hemorrhage IV DHE, intravenous dihydroergotamine CNS, central nervous system EEG, electroencephalogram BP, blood pressure EKG, electrocardiogram ICP, intracranial pressure TIA, transient ischemic attack. 

The activated partial thromboplastin time (APTT) measures the efficacy of the intrinsic and common pathways. Blood is collected and oxalate or citrate is added to arrest coagulation by binding calcium. In the laboratory, calcium is added to reverse the anticoagu-... 

ACEIs = angiotensin-converting enzyme inhibitors aPTT = activated partial thromboplastin time BP = blood pressure CBC = complete blood count HR = heart rate INR = international normalized ratio RR = respiratory rate Sq = serum creatinine. 

Baseline laboratory tests should be obtained and include a complete blood cell (CBC) count, platelet count, prothrombin time, activated partial thromboplastin time, and liver and renal function tests. Abnormal liver function tests may suggest liver involvement with tumor. However, patients with metastatic disease to the liver may have normal liver function tests, and abnormal liver function tests are not always indicative of metastatic disease. 

Anticoagulant Activity Assay. The anticoagulant activities of IV-acetylated heparin and all further derivatized heparins were determined based on activated partial thromboplastin time (APTT) assay methods (15). Bovine blood was collected in 3.8% sodium-citrated (9 parts blood to 1 part citrate solution) and centrifuged at 5000 x g for 15 min. The supernatant plasma was collected and pooled for subsequent APTT testing. Prior to testing plasma was kept refrigerated no longer than 6 h after... 

Hepatic injury can also alter the synthesis of the blood coagulation cascade and prolong prothrombin and activated partial thromboplastin times. These effects on vitamin K dependent coagulation factors II (prothrombin), VII, IX, and X and protein C, protein S, and protein Z tend to affect the prothombin time (PT) more frequently than the activated partial thromboplastin time (APTT) however in some cases of hepatotoxicity, the APTT changes may be more marked than those for PT (Pritchard et al. 1987). 

Mechanism and effects Regular heparin binds to and activates endogenous antithrombin 111 (ATlIl). The heparin-ATIll complex combines with and inactivates thrombin (activated factor 11) and several other factors, especially factor X. In the presence of heparin, antithrombin III inhibits the coagulation factors approximately 1000-fold faster than in its absence. Low doses of heparin also coat the endothelial walls of vessels and reduce the activation of clotting elements by these cells. Because it acts on preformed blood components, heparin is also active in vitro—almost instantaneously. The action of heparin is monitored with the activated partial thromboplastin time laboratory test (aPTT or PTT). 

Steroidal saponins isolated from anemarrhena inhibited platelet aggregation and activated partial thromboplastin time in human blood (Zhang et al. 1999). Another saponin inhibited PAF-induced platelet aggregation in rabbit blood (Dong and Han 1991). 

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