fill by capillary action. When blood reaches theend of the capillary bore in the neck of thepipette, filling is complete and will stopautomatically. The amount of blood collectedby the capillary tube is 10 Fl. Wipe any bloodoff the outside of the capillary tube, making sureno blood is removed from inside the capillarypipette. (An alternative source of blood is athoroughly mixed fresh venous blood sampleobtained by venipuncture. See figure 7-10,view B.)3. With one hand, gently squeeze the reservoir toforce some air out, but do not expel any diluent(fig. 7-11). Maintain pressure on the reservoir.With the other hand, cover the upper opening ofthe capillary overflow chamber with your indexfinger and seat the capillary pipette holder in thereservoir neck (see fig. 7-11).4. Release pressure on the reservoir and removeyour finger from the overflow chamber opening.Suction will draw the blood into the diluent inthe reservoir.5. Squeeze the reservoir gently two or three timesto rinse the capillary tube, forcing diluent intobut not out of the overflow chamber, releasingpressure each time to return diluent to thereservoir. Close the upper opening with yourindex finger and invert the unit several times tomix the blood sample and the diluent. Seefigure 7-12.6. For specimen storage, cover the overflowchamber of the capillary tube with the capillaryshield.7-12CAPILLARYPIPETTE SHIELDDIAPHRAGMHM3f0709Figure 7-9.—Puncturing the diaphragm of diluent with thecapillary pipette shield.ABHM3f0710Figure 7-10.—Drawing blood into the Unopette capillarytube: A. From a finger puncture; B. From a venous bloodsample.HM3f0711CAPILLARY OVERFLOWCHAMBERFigure 7-11.—Preparing reservoir to receive blood from thecapillary tube.
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