Lecture 5 Flashcards
Purpose of ESR
To detect the presence of inflammation caused by
• Infections
• lymphoproliferative disorders
• autoimmune diseases
What does ESR Aid in diagnosing:
- Multiple Myeloma
- Rheumatoid arthritis
- Lupus erythematosus
Theory of ESR
- Rate at which RBCs fall (sediment) within a set time (one hour)
- The red blood cells become sediment at the bottom of the tube leaving blood plasma at the top of the column
- The ESR is nonspecific, meaning that it does not tell the doctor exactly where the inflammation is occurring in the body
- Units mm/hr ( manual)
- Automated mmm/time
Increased Results (red cell falls more rapidly) of ESR
- Rouleaux – stacked like coins instead of separated in monolayer (caused by increased fibrinogen – protein)
- Fibrinogen (protein involve in inflammation)
- Immunoglobulin (protein involve in inflammation)
- Pregnancy
- Anemia
- Auto immune disorder (RA and lupus)
- Lymphoma
- Myeloma
Decreased Results (red cell falls slowly) **
- High RBC - polycythemia
- Some RBC shapes: example sickle cells
- Leukemia
- Congestive heart failure
- Hyperviscosity
Manual Westergren Method
200 mm open ended tube
• Black Top Tube (2.4 mL draw into 0.6 mL citrate)
• Many medical laboratories use lavender top EDTA sample.
• Difference in results are not usually clinically or statistically significant.
Procedure Manual Westergren
- Use pipette filler to fill ESR tube until cotton plug is wetted to prevent leaking.
- Set up vertically in rack; record mm that RBCs fell in 1 hour
Normal Range; Westergren
- males 0 - 15 mm /hr
* females 0 – 20 mm /hr
Wintrobe method
: 100 mm closed ended tube
• EDTA blood –lavender top tube
• Record mm blood falls in one hour
• Method not as sensitive as Westergren ESR
Reference range
• Males and Females: 0-9 mm/hr
Automated Methods
- specimen is collected in special vacuum tubes made specifically for the automated ESR instruments(Black Top vacutainer)
SEDIMAT: AUTOMATED READER
• random access of samples
• 15 minute test
• correlates with manual Westergren
ESR-100
30 min test using ESR vacuum tubes correlates with Westergren
• 100 channels
• Throughput 400 tests per hour
• Temperature compensation
• Tube employed: Special 8 x 120 mm tubes
• Reading time 15 minutes Random access
• On board printer, barcode and scanner
VES- MATIC Automated ESR
- Correlated to Westergren Reference method
- 30 positions
- Automated mixing
- Barcode reader for positive sample identification.
- Rapid results: - 20 minutes, standard mode - 10 minutes, fast mode
- Use Bi-level QC material
- Connectivity to LIS
- Small sample volume- 1ml
- Closed sample tube system reduces health and safety risks
Falsely Increased ESR
Tube not vertical Incorrect timing (too long) Room temp >25º C Incorrect mixing of sample Vibration of tube during test
Falsely Decreased ESR
Air bubbles in tube Incorrect timing (too short) Blood specimen below RT Fibrin clots Hemolyzed samples
Precaution and Technical Factors (Quality Assurance)
- use Bull’s eye level on ESR rack to ensure tubes are vertical(manual method)
- Test must be set up within 2hrs of blood collection
- Use approved commercial controls