AnticoagulationThe black-top tube employs a 0.129mol/L sodium citrate buffer system to anticoagulate blood specimens. Applicable for inflammatory disease monitoring. Advantages: unique value compared to modern inflammatory markers.
1. Monitoring Inflammatory Diseases
| Condition | Clinical Utility |
|---|---|
| Infections | Bacterial TB → ESR ↑↑ >100 mm/h |
| Autoimmune diseases | Active RA → ESR ↑ (combined with CRP) |
| Malignancies | Multiple myeloma → Persistent ESR ↑ (therapy monitor) |
Fill blood to the calibration mark → 2. Invert mix 8 times → 3. Place vertically in Westergren rack → 4. Stand undisturbed at RT for 60 min → 5. Measure plasma interface drop (mm) = ESR value.
| ESR (mm/h) | Clinical Implication |
|---|---|
| <20 (M) / <30 (F) | Normal |
| 20–50 | Mild elevation (e.g., chronic inflammation) |
| >50 | Significant elevation (active infection/tumor) |
Fill volume deviation:
±10% error → ESR deviation up to 30% (Must fill exactly to the mark!).ect.
2. Interfering Factors
| Factor | ESR Effect | Solution |
|---|---|---|
| Anemia (Hct<30%) | Falsely ↑ | Corrected ESR = ESR × [0.73+Hct] |
| Refrigerated sample | Falsely ↓ | Equilibrate to RT for 30 min |
| Underfilled tube | Clot formation | Discard and recollect |