Manual of basic techniques for a health laboratory - libdoc.who.int

9. Haematology 293Fig. 9.45 Materials for measuring theerythrocyte sedimentation rateFig. 9.46 Adding a blood sample to thetrisodium citrate solution3. Remove the needle from the syringe and add 1.6ml of blood to the test-tubecontaining anticoagulant (marked to contain a total of 2.0ml) (Fig. 9.46). Shakegently. Measurement of the ESR should begin within 2 hours of collection of theblood.4. Draw the citrated blood into the Westergren tube (using a rubber safety bulb) upto the 0-mm mark (Fig. 9.47).5. Place the tube in the Westergren stand, making sure that the tube is completelyupright (Fig. 9.48).Check that there are no air bubbles in the tube.Check that the stand is level.6. Leave on a bench away from vibration (e.g. not on the same bench as a centrifuge),free from draughts, not close to a central heating radiator and not in directsunlight.7. Wait 1 hour (set the timer to ring), then note the height of the column of plasmain mm graduations starting from the 0-mm mark at the top of the tube (Fig.9.49).9.7.4 ResultsThe result is expressed in millimetres per hour (mm/h).Reference rangeTable 9.9 shows the reference ranges for adults.Note: If a patient is dehydrated measurement of the ESR has little value.High valuesAny disease that produces plasma protein changes will increase the ESR. Theseinclude acute and chronic infections, myocardial infarctions and rheumatoid arthritis.The ESR is also increased in patients suffering from anaemia (see page 285).