MODIFIED WESTERGREN ERYTHROCYTE SEDIMENTATION RATE Flashcards
- Use well-mixed blood collected in_____ and dilute at four parts____ to one part____ or _____ (e.g., 2 mL blood and 0.5 mL diluent).
Alternatively, blood can be collected directly into special sedimentation test tubes containing_____.
EDTA
blood
3.8% sodium citrate or
0.85% sodium chloride
sodium citrate
Standard coagulation test tubes are not acceptable because the dilution is_____ parts blood to____ part sodium citrate.
nine
one
- Place the diluted specimen in a_____mm column with an internal diameter of_____mm or more.
200-mm
2.55 mm
Sources of Error
Erythrocyte Sedimentation Rate
1. If the concentration of anticoagulant is increased, the ESR will be….
2. The anticoagulants sodium or potassium oxalate and heparin cause the RBCs to_____ and falsely elevate the ESR.
3. A significant change in the_____ of the room alters the ESR.
4. Even a slight tilt of the pipette causes the ESR to_____.
falsely low as a result of sphering of the RBCs, which inhibits rouleaux formation.
shrink
temperature
increase
Sources of Error
Erythrocyte Sedimentation Rate
- Blood specimens must be analyzed within_____ of collection if kept at room temperature (18° to 25° C) specimen is allowed to sit at room temperature for more than 4 hours, the RBCs start to become_____, which may inhibit the formation of rouleaux.
Blood specimens may be stored at_____ up to 24 hours before testing, but must be rewarmed by holding the specimen at ambient room temperature for at least______ before testing. - Bubbles in the column of blood_____ the test results.
4 hours
spherical
4° C
15 minutes
invalidate
Sources of Error
Erythrocyte Sedimentation Rate
- The blood must be filled properly to the______ mark at the beginning of the test.
- A_____ specimen cannot be used.
- The tubes must not be subjected to____ on the laboratory bench, which can falsely____ the ESR.
zero
clotted
vibrations; increase
Sources of Error
Erythrocyte Sedimentation Rate
- Hematologic disorders that prevent the formation of rouleaux (e.g., the presence of sickle cells and spherocytes)______ the ESR.
- The ESR of patients with severe anemia is of little diagnostic value, because it will be falsely_____.
decrease
elevated
Age (0-50)
Male
Female
<15 mm/h
<20 mm/h
Age (51-85)
Male
Female
<20 mm/h
<30 mm/h
Age (>85)
Male
Female
< 30 mm/h
<42 mm/h
causes red blood cells to stick together and sink faster
Inflammation
Procalcitonin (PCT)
What it Measures
Type of Marker
Response Time
Peak Levels
Retum to Normal
Influenced By
Prohormone of calcitonin, produced during systemic infections
Specific marker for bacterial infections
Very rapid (within 2-4 hrs)
Peaks within 24 hrs
Rapidly after infection resolves
Strongly related to bacterial infections
C-Reactive Protein (CRP)
What it Measures
Type of Marker
Response Time
Peak Levels
Retum to Normal
Influenced By
Acute-phase protein produced by the liver
Direct inflammatory marker
Rapid (within 6-8 hrs)
Peaks within 24-48 hrs
Quickly (within 24-48 hrs)
Less influenced by external factors
Erythrocyte Sedimentation
Rate (ESR)
What it Measures
Type of Marker
Response Time
Peak Levels
Retum to Normal
Influenced By
Rate of RBC sedimentation in plasma
Indirect inflammatory marker
Slow (24-48 hrs to rise)
Peaks in days
Slowly (days to weeks)
Plasma proteins (fibrinogen, globulins), anemia, pregnancy, age
