Consider idiopathic thrombocytopenic purpura, thrombotic thrombocytopenic purpura, malignancy, viral disease
Normal | Normal | Platelet Function Analyzer-100, which checks the amount of time it takes platelets to aggregate onto an aperture coated with a collagen/epinephrine membrane and a collagen/adenosine diphosphate membrane | Is there a prolonged aggregation time with both membranes? |
Normal | Abnormal | Partial thromboplastin time mixing study | Does partial thromboplastin time correct (normalize)? |
Abnormal | Normal | Determine if the patient is malnourished or if there is clinical suspicion for vitamin K deficiency | Does prothrombin time correct or normalize with administration of vitamin K? |
Abnormal | Abnormal | Consider disseminated intravascular coagulopathy | Consider factor assays for factor deficiencies |
Verify no use of warfarin (Coumadin) or heparin | |||
Verify no liver disease |
A 52-year-old man gave a lifelong history of easy bruising and excessive bleeding following tooth extractions. After taking aspirin, he developed severe nosebleeds. Family history was remarkable for heavy vaginal bleeding in his mother and sister.
A 35-year-old woman presents with bruising of the upper thighs. She denies menorrhagia or other bleeding symptoms. She reports two vaginal deliveries, an appendectomy, and a tubal ligation, all without excessive bleeding. Her family history does not suggest a bleeding disorder and, except for the simple bruising, her physical examination is unremarkable.
A 43-year-old woman was admitted to the hospital with a large hematoma in the right thigh. She had no history of trauma or spontaneous bleeding and had tolerated minor surgical procedures in the past without bleeding. Her family history was negative and she had not been on any medications associated with increased bleeding risk.
Taking a personal history starts with a list of screening questions based on a bleeding score system ( Table 3 ) . 3 This bleeding score system is a clinical decision rule to screen for von Willebrand's disease, the most common inherited bleeding disorder. This disease results from a quantitative or qualitative defect in von Willebrand's factor, which is required for platelet aggregation. Although the bleeding score system is intended for the diagnosis of von Willebrand's disease, it lists criteria necessary to diagnose other bleeding disorders as well. 4 – 9 A history of bleeding that requires surgical intervention, blood transfusion, or replacement therapy is a significant red flag for a bleeding disorder and, therefore, receives a high number of points. More information on the bleeding score can be found at http://www.euvwd.group.shef.ac.uk/bleed_score.htm . Table 4 3 indicates the probability of von Willebrand's disease based on the bleeding score.
Epistaxis | — | No or trivial (< 5 episodes per year) | > 5 episodes per year or lasts > 10 minutes | Consultation only | Packing, cauterization, or antifibrinolytic | Blood transfusion, replacement therapy, or desmopressin (DDAVP) |
Cutaneous (bruises, petechia, subcutaneous hematoma) | — | No or trivial (< 1 cm) | > 1 cm and no trauma | Consultation only | — | — |
Bleeding minor wounds | — | No or trivial (< 5 episodes per year) | > 5 episodes per year or lasts > 5 minutes | Consultation only | Surgical hemostasis | Blood transfusion, replacement therapy, or desmopressin |
Oral cavity (bleeding gums [spontaneous or with brushing], bites to lip and tongue, tooth eruption) | — | No | Bleeding noted at least once | Consultation only | Surgical hemostasis or antifibrinolytic | Blood transfusion, replacement therapy, or desmopressin |
Gastrointestinal bleeding (hematemesis, hematochezia, melena) | — | No | Associated with angiodysplasia, hemorrhoids, portal hypertension, ulcer | Spontaneous | Surgical hemostasis, blood transfusion, replacement therapy, desmopressin, or antifibrinolytic | |
Tooth extraction | No bleeding in at least two extractions | None performed or no bleed in one extraction | Bleeding noted in < 25% of all procedures | Bleeding noted in > 25% of all procedures, but no intervention | Resuturing or packing | Blood transfusion, replacement therapy, or desmopressin |
Surgery | No bleeding in at least two surgeries | None performed or no bleeding in one surgery | Bleeding noted in < 25% of all procedures | Bleeding noted in > 25% of all procedures, but no intervention | Surgical hemostasis or antifibrinolytic | Blood transfusion, replacement therapy, or desmopressin |
Menorrhagia | — | No | Consultation only | Antifibrinolytics, pill use | Dilatation and curettage, iron therapy | Blood transfusion, replacement therapy, desmopressin, or hysterectomy |
Postpartum hemorrhage | No bleeding in at least two deliveries | No deliveries or no bleeding in one delivery | Consultation only | Dilatation and curettage, iron therapy, antifibrinolytics | Blood transfusion, replacement therapy, or desmopressin | Hysterectomy |
Muscle hematomas | — | Never | Post-trauma, no therapy | Spontaneous, no therapy | Spontaneous or traumatic, requiring desmopressin or replacement therapy | Spontaneous or traumatic, requiring surgical intervention or blood transfusion |
Hemarthrosis | — | Never | Post-trauma, no therapy | Spontaneous, no therapy | Spontaneous or traumatic, requiring desmopressin or replacement therapy | Spontaneous or traumatic, requiring surgical intervention or blood transfusion |
Central nervous system bleeding | — | Never | — | — | Subdural, any intervention | Intracerebral, any intervention |
−3 | 0.00 | 0.0 |
−2 | 0.04 | 0.2 |
−1 | 0.10 | 0.5 |
0 | 0.13 | 0.7 |
1 | 1.60 | 8.0 |
2 | 2.20 | 10.0 |
3 | 3.00 | 13.0 |
4 | 16.00 | 43.0 |
A positive family history increases the risk of a bleeding disorder and is reason to initiate a work-up, 10 , 11 especially in women with menorrhagia. 12 Many bleeding disorders have an inheritance pattern, including the X-linked recessive hemophilias. Family history is especially important in children because they may not have had the opportunity to experience a hemostatic challenge (e.g., surgery, delivery, tooth extraction). In a study of children referred to a tertiary care center with either a personal or family history of bleeding, a positive family history was significantly associated with a diagnosis of a bleeding disorder. 10
The patient in case study one who had a history of bruising and bleeding after tooth extraction would have a bleeding score of at least 4 (epistaxis: 1; bruising: 1; and tooth extraction: 2). This score, coupled with his family history of menorrhagia in the mother and sister, creates a high index of suspicion for a bleeding disorder, even before any laboratory testing is obtained.
The bleeding score system assigns a negative number if there is no significant bleeding after a hemostatic challenge. The importance of the “negative history” is illustrated by the woman in case study two who had bruising on her upper thigh (score: 1); an appendectomy and tubal ligation without a significant bleed (score: −1); two vaginal deliveries without a significant bleed (score: −1); and no other bleeding symptoms (score: 0). This gives her a total bleeding score of −1.
As illustrated in case study three, a patient may have a low bleeding score and a negative family history, but still present with physical examination findings suggestive of a bleeding disorder. Pertinent physical examination findings of bleeding and bruising disorders are listed in the second column of Table 1 .
Table 5 4 – 6 lists medications that cause bleeding or bruising. The physician should not rule out a bleeding disorder just because a patient is receiving one of these medications, especially if the patient has a high bleeding score. Medications may cause the disease to manifest itself with bleeding symptoms, as illustrated in case study one.
Aspirin |
Clopidogrel (Plavix) |
Heparin |
Nonsteroidal anti-inflammatory drugs |
Warfarin (Coumadin) |
Cephalosporins |
Ginkgo biloba |
Gold |
Interferon |
Metaxalone (Skelaxin) |
Penicillins |
Propothiouricil |
Selective serotonin reuptake inhibitors |
Testosterone replacement |
Tricyclic antidepressants |
Understanding of the complexity of hemostasis has greatly increased since it was originally described in 1964. 13 , 14 Interactions of basic “ingredients” are required for a clot to form, and a qualitative or quantitative defect of any “ingredient” can result in a bleeding or bruising disorder. Knowledge of basic clot formation can help the physician to understand these disorders and their initial laboratory work-up, which includes complete blood count with platelet count, peripheral blood smear, prothrombin time (PT), and partial thromboplastin time (PTT).
A shortage of platelets (thrombocytopenia) can be detected on complete blood count. A peripheral blood smear can help to rule out pseudothrombocytopenia and to look for abnormally shaped platelets.
The PT measures the factors of the extrinsic and common pathways. Deficiencies of these factors (most notably factor VII) will prolong the PT. Vitamin K is required for the synthesis of the critical factors of these pathways; therefore, patients with vitamin K deficient conditions may have a prolonged PT. 15
The PTT measures the factors of the intrinsic and common pathways. Deficiencies of these factors, including factor VIII (hemophilia A) and factor IX (hemophilia B), will prolong the PTT. Factor VIII levels may be low in patients with von Willebrand's disease; therefore, these patients could present with a prolonged PTT. 1
Inhibitors, autoantibodies that attach to a factor and render it useless for clot formation, can also prolong the PTT. The most common inhibitors are the factor VIII inhibitors and the lupus anticoagulant (“lupus anticoagulant” is incorrectly named and typically presents more often as thrombosis than as bleeding). A factor VIII inhibitor should be suspected in anyone who has no history of bleeding, but develops significant bleeding (such as the woman with the large spontaneous hematoma in case study three) and has a prolonged PTT. 16
Platelet function activity.
Traditionally, the test of choice for evaluation of platelet function was bleeding time; however, the use of bleeding time to predict surgical bleeding has been questioned 17 , 18 and its use has been discouraged or eliminated at some institutions. 1 , 19 The Platelet Function Analyzer (PFA)-100 has been shown to be superior to bleeding time in detecting von Willebrand's disease. 20 – 22
The PFA-100 simulates the formation of the platelet plug in vivo by passing the patient's blood through an aperture coated with collagen/epinephrine and collagen/adenosine diphosphate. In patients with von Willebrand's disease and other platelet function disorders, the amount of time required for the platelets to aggregate from both collagen/epinephrine and collagen/adenosine diphosphate is prolonged. A prolonged time to clot to just collagen/epinephrine usually indicates a drug effect, such as from aspirin.
The reported sensitivity of the PFA-100 for diagnosing von Willebrand's disease and other platelet function disorders is 88 to 90 percent with a specificity of 86 to 94 percent. 23 , 24 Studies have concluded that the PFA-100 is a useful screening test, 23 , 24 but this conclusion is still being debated. 24 – 28 Although the PFA-100 is more sensitive than bleeding time, a negative result should not preclude further testing for von Willebrand's disease or other platelet function disorders. If the PFA-100 is negative, the physician should review the initial history to determine if further testing should be performed.
A mixing study determines if the patient has a clotting factor deficiency or an inhibitor to a factor. When one part of the patient's blood is mixed with one part of normal blood, the inhibitor in the patient's blood disables the factor in the normal blood. The PTT stays prolonged and does not “correct.” Inhibitor assays are then performed to identify which inhibitor is present. When the blood from a patient with a factor VIII deficiency is mixed with normal blood, the PTT should normalize or correct. Factor assays are then performed to identify which factor is deficient.
The sensitivity of the mixing study to detect a lupus anticoagulant is 95 percent with a specificity of 60 percent. 29 In a study of 42 laboratories asked to analyze known samples, 30 97.5 percent correctly identified the sample with a lupus anticoagulant and 90.2 percent correctly reported the negative serum sample as negative. However, 53.6 percent did not correctly identify the factor VIII inhibitor and many did poorly with contaminated specimens. Therefore, knowledge of a laboratory's limitations, especially when trying to identify an inhibitor that is not a lupus anticoagulant, is helpful when interpreting the results.
If the laboratory work-up does not diagnose a bleeding disorder, but there is still high suspicion based on personal and family history, the patient should be referred to a hematologist. If von Willebrand's disease, a factor VIII inhibitor, or factor deficiencies are discovered, referral is based on the diagnosis and severity, as well as the comfort level of the physician. If the history, physical examination, or the routine laboratory studies are abnormal in the preoperative assessment, surgery should be delayed until a cause can be determined with a work-up or by referral.
Case One . Laboratory testing included a normal blood count and platelet count. A PFA-100 test was abnormal to collagen/epinephrine and collagen/adenosine diphosphate. Further testing was diagnostic for von Willebrand's disease.
Case Two . A complete blood count, PT, PTT, and PFA-100 were normal. The patient was reassured that with a low bleeding score, a negative family history, and an unremarkable physical examination, she most likely has purpura simplex (easy bruising). She was told to follow up if her symptoms got worse or if she had any new symptoms.
Case Three . Laboratory evaluation included a hemoglobin count of 7 g per dL (70 g per L), a platelet count of 400 × 10 3 per μL (400 × 10 9 per L), a PT of 12 seconds, and a PTT of 100 seconds. A mixing study did not return the PTT to normal. Measurement of factor VIII showed a level of 1 percent, and an assay for the presence of a factor VIII inhibitor showed a high-titer inhibitor.
Penza S, Kraut E. Coagulation disorders. The Ohio State University Medical Center, Center for Continuing Medical Education. http://ccme.osu.edu/cmeactivities/onlineeducation/ondemand/program/index.cfm?id=281 . Accessed Sepetember 19, 2007
Zehnder JL. Clinical use of coagulation tests. UpTo-Date, 2007. http://www.uptodate.com [Subscription required]. Accessed September 19, 2007.
Tosetto A, Rodeghiero F, Castaman G, et al. A quantitative analysis of bleeding symptoms in type 1 von Willebrand disease: results for a multicenter European study (MCMDM-1 VWD). J Thromb Haemost. 2006;4(4):766-773.
Sham RL, Francis CW. Evaluation of mild bleeding disorders and easy bruising. Blood Rev. 1994;8(2):98-104.
Valente MJ, Abramson N. Easy bruisability. South Med J. 2006;99(4):366-370.
Colon-Otero G, Cockerill KJ, Bowie EJ. How to diagnose bleeding disorders. Postgrad Med. 1991;90(3):145-150.
Schafer AI. Approach to bleeding. In: Loscalzo J, Schafer AI, eds. Thrombosis and Hemorrhage . 3rd ed. Philadelphia, Pa.: Lipincott Williams & Wilkins, 2003:318–377.
Giansily-Blaizot M, Schved JF. Potential predictors of bleeding risk in inherited factor VII deficiency. Clinical, biological and molecular criteria. Thromb Haemost. 2005;94(5):901-906.
Giansily-Blaizot M, Biron-Andreani C, Aguilar-Martinez P, et al. Inherited factor VII deficiency and surgery: clinical data are the best criteria to predict the risk of bleeding. Br J Haematol. 2002;117(1):172-175.
Acosta M, Edwards R, Jaffe IM, Yee DL, Mahoney DH, Teruya J. A practical approach to pediatric patients referred with an abnormal coagulation profile [published correction appears in Arch Pathol Lab Med . 2005;129(11):1368]. Arch Pathol Lab Med. 2005;129(8):1011-1016.
Allen GA, Glader B. Approach to the bleeding child. Pediatr Clin North Am. 2002;49(6):1239-1256.
Ragni MV, Bontempo FA, Hasset AC. von Willebrand disease and bleeding in women. Haemophilia. 1999;5(5):313-317.
Davie EW, Ratnoff OD. Waterfall sequence for intrinsic blood clotting. Science. 1964;145:1310-1312.
Macfarlane RG. An enzyme cascade in the blood clotting mechanism, and its function as biological amplifier. Nature. 1964;202:498-499.
Patel P, Mikhail M. Vitamin k deficiency. Emedicine. http://www.emedicine.com/med/topic2385.htm . Accessed September 19, 2007.
Green D. Spontaneous inhibitors to coagulation factors. Clin Lab Haematol. 2000;22(suppl 1):21-25.
Gewirtz AS, Miller ML, Keys TF. The clinical usefulness of the preoperative bleeding time. Arch Pathol Lab Med. 1996;120(4):353-356.
De Caterina R, Lanza M, Manca G, Strata GB, Maffei S, Salvatore L. Bleeding time and bleeding: an analysis of the relationship of the bleeding time test with parameters of surgical bleeding. Blood. 1994;84(10):3363-3370.
Massachusetts General Hospital. Bleeding time [CO006500]. http://www.massgeneral.org/pathology/coagbook/CO006500.htm. Accessed September 19, 2007
Kerényi A, Schlammadinger A, Ajzner E, et al. Comparison of PFA-100 closure time and template bleeding time of patients with inherited disorders causing defective platelet function. Thromb Res. 1999;96(6):487-492.
Dean JA, Blanchette VS, Carcoa MD, et al. von Willebrand disease in a pediatric-based population—comparison of type 1 diagnostic criteria and use of the PFA-100 and a von Willebrand factor/collagen-binding assay. Thromb Haemost. 2000;84(3):401-409.
Posan E, McBane RD, Grill DE, Motsko CL, Nichols WL. Comparison of PFA-100 testing and bleeding time for detecting platelet hypofunction and von Willebrand disease in clinical practice. Thromb Haemost. 2003;90(3):483-490.
Harrison P, Robinson M, Liesner R, et al. The PFA-100: a potential rapid screening tool for the assessment of platelet dysfunction. Clin Lab Haematol. 2002;24(4):225-232.
Koscielny J, Kiesewetter H, von Tempelhoff GF. More on: platelet function analyzer (PFA-100) closure time in the evaluation of platelet disorders and platelet function. J Thromb Haemost. 2006;4(6):1426-1427.
Hayward C, Harrison P, Cattaneo M, Ortel TL, Rao AK. The Platelet Physiology Subcommittee of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostatis. Platelet function analyzer (PFA)-100 closure time in the evaluation of platelet disorders and platelet function. J Thromb Haemost. 2006;4(2):312-319.
Serebruany VL. Platelet function analyzer (PFA-100) closure time in the evaluation of platelet disorders and platelet function: a rebuttal. J Thromb Haemost. 2006;4(2):1428-1429.
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Step 1. Chapter 11 Special Collections and Point-of-Care Testing Case Studies 239 CASE STUDY 11-1: PROTHROMBIN TEST COLLECTION During clinical practicum, a phlebotomy student found that the requirements for drawing prothrombin times were not the same as he was taught in class His clinical coordinator made it very clear that he was to follow ...
CASE STUDY 1 1 - 1: PROTHROMBIN TEST COLLECTION. During clinical practicum, a phlebotomy student was asked to collect a CBC and prothrombin time from a patient, the student knew that the order of draw at this facility was citrate first, no discard tube. While starting to draw the specimen the vein rolled. Certain that the needle had slipped ...
The Prothrombin Time (PT) test evaluates the time it takes for your blood to clot, it is an extrinsic pathway. Prothrombin is a precursor for thrombin which originates in your liver. PT test clotting factors are factor XII, factor XI, Factor IX, factor VIII, and factor X; each serves as an enzyme that catalyzes the next step.
case study week 1 pt tests assess the levels of prothrombin, fibrinogen, and normal factors and 10 in our blood. this indicates that the extrinsic routes are ... The intrinsic pathways are linked to PTT tests, and the components that are involved are 8, 11, and 12. ... A&P 255 - EXAM 2 - exam study guide. Anatomy and Physiology 3 100% (11) 3 ...
10.Inoculate medium as required. 11.Invert bottle several times. 12.Clean patient's skin if applicable. 13.Label specimen containers with required ID info which includes name, DOB, time collected, indicate where it was drawn from (RH, RA, LH, LA) 14.Dispose of used & contaminated materials.
Discussion 8- wkbk Pg 239 Case Study 11-1: Prothrombin Test Collection Week 10 . Spring Break . Week 11 Chapter 12: Computers and Specimen Handling and Processing Assignment: wkbk Pg. 242244, 24- 5, 252, Discussion 9- wkbk Pg. 257 Case Study 12-1:
Explore the Case Study 11 Examination learning module on F.A. Davis PT Collection. F.A. Davis PT Collection is a subscription-based resource from McGraw Hill that features trusted medical content from the best minds in medicine.
Burn patient -- Case 4. 2-year-old child -- Case 5. Obese patient -- Case 6. Repeat of a newborn screening test -- Ch. 2. Coagulation -- Case 7. Inadequate tube fill -- Case 8. Patient on "blood thinner" -- Case 9. Prothrombin time -- Case 10. Karyotyping -- Case 11. Complications in a postpartum patient -- Case 12. Unstoppable nose bleed ...
1. median. 2. median cephalic. 3. median basilic. 4. last choice because it lies near anterior and posterior branches of median cutaneous nerve and brachial artery. 6-2. a specimen processor receives a STAT chemistry specimen on a patient in the ER at 0900. the specimen was collected at 0855.
19 of 49. Definition. used to perform glucose tolerance test. -patients drinks determined dose of glucose beverage, -finish within 5 min. - note times patient finished to start timing calculate rest of collection times. -30 min, 1 hour, 2, hours, 3 hours. -collect blood and urine specimen at computed times.
Prothrombin Time Test: Purpose, Procedure, and Results
Week 1 case study case study: coagulation both the pt (prothrombin time) and ptt (partial thromboplastin time) tests are used to examine the capacity to however. Skip to document. University; ... A&P 255 - EXAM 2 - exam study guide. Anatomy and Physiology 3 100% (9) 21.
Chapter 11 - Hemostasis, Wound Healing, and Wound Closure. 5.0 (2 reviews) Flashcards; Learn; Test; Match; Q-Chat; ... N112 Pathopharm Exam 1 Study Set. 325 terms. sonelis. Preview. NURS 2270 Exam 3 - Musculoskeletal. 15 terms. Morgan_Kochis4. ... Formed from the reaction of prothrombin with thromboplastin.
9.4 - 12.2 seconds. Critical value: INR >5.0. Recommended therapeutic ranges for oral anticoagulant therapy: INR 1.2 - 1.5 Prevention of catheter-related venous thrombosis; INR 2.0 - 3.0 Treatment of venous or pulmonary embolism, prevention of systemic embolism, tissue heart valves, atrial fibrillation, valvular heart disease; INR 2.5 - 3.5 ...
Background A substantial fraction of all American healthcare expenditures are potentially wasted, and practices that are not evidence-based could contribute to such waste. We sought to characterize whether Prothrombin Time (PT) and activated Partial Thromboplastin Time (aPTT) tests of preoperative patients are used in a way unsupported by evidence and potentially wasteful. Methods and Findings ...
Case Study: Coagulation. Prothrombin time tests for is for clotting factor VII which is also called PT. Thromboplastin time tests clotting factors VIII, IX, XI, and XII which is also called PTT. Clotting factors for these are important for our body as they help us start the healing process forming blood clots near the injured area (Saladin, 2020).
Study with Quizlet and memorize flashcards containing terms like What is the correct procedure when using a winged collection device (butterfly) to draw a light-blue top tube intended for a coagulation test if this is the first tube that will be collected in the draw?, A test used to evaluate the abnormalities in the intrinsic coagulation pathway and to monitor heparin therapy is called:, The ...
Bleeding and Bruising: A Diagnostic Work-up