Pathology
Haematology
Question 29 of 180
Regarding screening tests for clotting, which of the following statements is CORRECT:
Answer:
| Screening Test | Normal Time | Abnormalities Indicated by Prolongation | Causes |
|---|---|---|---|
| Thrombin Time (TT) | 14 - 16 seconds | Deficiency/abnormality of fibrinogen or inhibition of thrombin | DIC, heparin therapy |
| Prothrombin Time (PT) | 10 - 14 seconds | Deficiency/inhibition of coagulation factors: VII, X, V, II, fibrinogen (extrinsic and common pathway) | Liver disease, warfarin therapy, DIC |
| Activated Partial Thromboplastin Time (APTT) | 30 - 40 seconds | Deficiency/inhibition of coagulation factors: XII, XI, IX, VIII, X, V, II, fibrinogen (intrinsic and common pathway) | Haemophilia, Christmas disease, DIC, liver disease, warfarin therapy, heparin therapy |
| Fibrinogen Quantitation | x | Fibrinogen deficiency | DIC, liver disease |
Abnormal Bleeding
Pathology / Haematology / Coagulation Disorders
Last Updated: 19th June 2019
Abnormal bleeding may result from:
- Vascular disorders
- Thrombocytopaenia
- Defective platelet function
- Defective coagulation
Clinical Features
The pattern of bleeding is relatively predictable depending on the aetiology. Vascular and platelet disorders tend to be associated with bleeding from bleeding from mucous membranes and into the skin, whereas in coagulation disorders the bleeding is often into joints or soft tissue.
| Platelet/Vessel Wall Disease | Coagulation Disease | |
|---|---|---|
| Mucosal Bleeding | Common | Rare |
| Petechiae | Common | Rare |
| Deep haematomas | Rare | Characteristic |
| Bleeding from skin cuts | Persistent | Minimal |
| Gender | Equal | >80% male |
Screening Tests
A number of simple tests are employed to assess the platelet, vessel wall and coagulation components of haemostasis.
- Blood count and blood film examination
- Platelet count
- Screening tests of coagulation (see table below)
- Prothrombin time (may be expressed as international normalised ratio INR)
- Activated partial thromboplastin time (APTT)
- Thrombin (clotting) time
- Specific assays of coagulation factors
- Tests of platelet function
- Platelet aggregation tests
- Platelet adhesion assays
- Platelet function analysis-100 (PFA-100) test
- Tests of fibrinolysis
- Thromboelastography (TEG) or thromboelastometry (ROTEM)
- D-dimer
| Screening Test | Normal Time | Abnormalities Indicated by Prolongation | Causes |
|---|---|---|---|
| Thrombin Time (TT) | 14 - 16 seconds | Deficiency/abnormality of fibrinogen or inhibition of thrombin | DIC, heparin therapy |
| Prothrombin Time (PT) | 10 - 14 seconds | Deficiency/inhibition of coagulation factors: VII, X, V, II, fibrinogen (extrinsic and common pathway) | Liver disease, warfarin therapy, DIC |
| Activated Partial Thromboplastin Time (APTT) | 30 - 40 seconds | Deficiency/inhibition of coagulation factors: XII, XI, IX, VIII, X, V, II, fibrinogen (intrinsic and common pathway) | Haemophilia, Christmas disease, DIC, liver disease, warfarin therapy, heparin therapy |
| Fibrinogen Quantitation | x | Fibrinogen deficiency | DIC, liver disease |
Report A Problem
Is there something wrong with this question? Let us know and we’ll fix it as soon as possible.
Loading Form...
- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
