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Coag SCC
Coag all tests FINAL 4/2012
Question | Answer |
---|---|
COMMON PATHWAY QUIZ | COMMON PATHWAY QUIZ |
List, in proper activation sequence, the common pathway coagulation factors. Include all factors, precursors/zymogens/cofactors | X (IV + VIII + PPL) = Xa act. prothrom prothrom (IV + V + PPL) = thrombin act. fibrinogen |
A powerful enzyme necessary for clot formation is which of the following? thrombin PPL fibrinogen calcium | Thrombin |
The factor within the common pathway that stabilizes the fibrin clot | XIII |
All of the following factors are found in the common pathway, EXCEPT: XIII X I VI | VI |
Elevated levels of fibrinogen can be found in all of the following conditions, EXCEPT: pregnancy malignancy DIC acute infections | DIC |
A congenital factor I deficiency in which there is a certain amount of nonfunctional fibrinogen, is known as: afibrinogenemia dysfibrinogenemia hypofibrinogenemia hyperfibrinogenemia | dysfibrinogenemia |
A coagulation test that is used to detect a deficiency or lack of factor XIII is known as:urea solubility test thrombin time (TT) test quantitatrive fibrinogen assay Reptilase (Atroxin) time | Urea solubility test |
What is another name for the unstable fibrin polymers that are formed during clot formation? | primary hemostatic plug |
What is another name for the stable fibrin polymers that are formed during clot formation? | secondary hemostatic plug |
secondary hemostatic plug | clot retraction |
A typical normal patient reference range for a fibrinogen assay is: 100-200 mg/dL 200-400 mg/dL 400-800 mg/dL none of the above | 200-400 mg/dL |
True or False: Clotted specimens can be used for routine coagulation testing. True False | False |
By what mechanism(s) is the common pathway activated? | The common pathway is activated by complexes formed in the extrinsic/tissue and intrinsic pathways. |
Briefly explain what is meant by a "quantitative" coagulation factor deficiency | This means there is a defect in the synthesis of the factor, leading to a decreased concentration (amount) being produced. |
Briefly explain what is meant by a "qualitative" coagulation factor deficiency. | This means there is synthesis of a defective factor taking place, leading to normal amounts of an inactive or abnormally functioning factor being produced. |
Explain the principle of the quantitative fibrinogen assay | Explain the principle of the quantitative fibrinogen assay |
Explain the principle of the 5M urea solubility test | Unstable clots (due to insufficient amounts of factor XIII not being present) will dissolve in 5M urea. Stable clots (due to adequate amounts of factor XIII being present) will not dissolve in 5M urea |
Control ranges | evaluate the validity of a test procedure.They are calculated using quality control materials and establishing a range. To make sure procedures, techs, analyzer, etc., are functioning properly. All this is necessary to report patient results. |
Normal patient reference ranges | Ranges calculated from the results of normal patients. Normal patient reference ranges aid the physician in determining whether a patient is "ill" or "well". Patient results outside the normal patient reference range means there is something wrong |
INTRINSIC PATHWAY QUIZ | INTRINSIC PATHWAY QUIZ |
List, in proper activation sequence, the intrinsic pathway coagulation factors. Include all factors, precursors/zymogens/cofactors | Prekall to Kall w/ HMWK, kallkrien converts XII to XIIa XIIa w/ HMWK, converts XI to XIa XIa w/ coagulation factor IV (calcium), activates IX to IXa IXa w/ IV(calcium)-VIII-PPL complex, activates X to Xa. |
What is the coagulation procedure most commonly performed to monitor heparin therapy? | APTT |
What is the therapeutic anticoagulant range for APTT's? | 1.5-2.5 x's normal patient ranges |
What is the anticoagulant used most often for routine coagulation testing? | BUFFERED SODIUM CITRATE |
The intrinsic pathway is activated (initiated) by the activation of which coagulation factor? XIII I XII IX | XII |
Give the names of the two precursor substances needed for activation of the intrinsic pathway. | Prekallkrein and HMWK |
True or False: Hemolyzed specimens may be used in routine coagulation testing. | FALSE |
In general, a normal patient reference range for APTT's is which of the followiing? 1.5-2.5 seconds 9-14 seconds 25-40 seconds none of the above | 25-40 SECONDS |
All are indications for performing an APTT, EXCEPT: evaluating factor deficiencies in the intrinsic pathway detecting presence of circulating anticoagulants (inhibitors) monitoring heparin therapy diagnosing Hemophilia A | diagnosing Hemophilia A |
Intrinsic pathway abnormalities include all of the following, EXCEPT: Hemophilia A acquired/inherited factor deficiencies vascular abnormalities Hemophilia B | vascular abnormalities |
the following may cause prolonged APTT results, EXCEPT: liver disease DIC presence of platelets in the plasma inherited coagulation factor deficiencies | presence of platlets in plasma |
the following may cause prolonged APTT results, EXCEPT: liver disease DIC presence of platelets in the plasma inherited coagulation factor deficiencies | platelets |
the following may cause prolonged APTT results, EXCEPT: liver disease DIC presence of platelets in the plasma inherited coagulation factor deficiencies | All coagulation factors, cofactors, zymogens, etc. are contained within the plasma |
At what temperature is most routine coagulation testing, including APTT testing, performed? | 37C |
Why are normal and abnormal controls run each time APTT testing is performed? | To lend validity to APTT procedures, reagents, personnel performance, etc. |
How should the abnormal control range compare to anticoagulated patient APTT results? | How should the abnormal control range compare to anticoagulated patient APTT results? |
Give the purpose of the following reagents used in the APTT procedure: a. calcium b. partial thromboplastin c. activator | Give the purpose of the following reagents used in the APTT procedure: a. calcium b. partial thromboplastin c. activator |
How can incubation of a patient's plasma at 37C for more than 5 minutes affect the APTT results? | Incubation may decrease levels of coagulation factors V and VIII, which are heat sensitive = heat labile factors. This will, in turn, prolong the APTT results. |
Briefly explain the principle of the APTT test. | Pt plasma + Calcium + activator + partial thromboplastin (plt substitute) = clot formation |
EXTRINSIC PATHWAY QUIZ | EXTRINSIC PATHWAY QUIZ |
Explain the appropriate activation sequence of the extrinsic/tissue pathway. List the coagulation factors in their proper activation sequence. Include all factors, cofactors, zymogens, etc. | tissue injury 2. tissue injury releases coagulation factor III (tissue factor) into the blood 3. III activates VII to VIIa 4. III-VIIa complex together 5. and with the help of coagulation factor IV (calcium) the III-VIIa-IV complex activates X to Xa |
What does PT stand for? | protime or prothrombin time |
What are two indications for performing a PT test? | deficiency of one or more coagulation factors and to monitor anticoagulation therapies |
deficiency of one or more coagulation factors and to monitor anticoagulation therapies | Coumadin (Warfarin) |
The Protime test is a screening method for which pathway of the coagulation mechanism? | extrinsic/tissue pathway |
ROUTINE coagulation studies are performed on specimens collected with which type of anticoagulant? What color is the top of this vacutainer tube? | 3.2% buffered sodium citrate, the vacutainer tube top is light blue |
What do the initials INR stand for? | international normalized ratio |
All of the following are considered common causes of a prolonged Protime test, EXCEPT: vitamin K deficiency liver disease hemolysis oral anticoagulation therapy | hemolysis |
What is the purpose of the INR in protime testing? Be specific. | The INR provides a convenient method for standardizing the monitoring of oral anticoagulant therapy no matter which laboratory a patient goes to. |
What is the formula for calculating an INR? | (PT of patient/PT normal) to the power of ISI |
Given the following results, calculate the INR. ISI = 2.4, Patient protime = 18.5 sec, mean normal protime = 11.5 sec | (18.5/11.5)^2.4=3.1 |
Why must plasma used for prothrombin time/INR testing be free from platelets (platelet-poor plasma)? | The presence of platelets in the plasma can shorten the clotting time. |
The presence of platelets in the plasma can shorten the clotting time. | 9:1 |