fill by capillary action. When blood reaches the
end of the capillary bore in the neck of the
pipette, filling is complete and will stop
automatically. The amount of blood collected
by the capillary tube is 10 Fl. Wipe any blood
off the outside of the capillary tube, making sure
no blood is removed from inside the capillary
pipette. (An alternative source of blood is a
thoroughly mixed fresh venous blood sample
obtained by venipuncture.
See figure 7-10,
view B.)
3.
With one hand, gently squeeze the reservoir to
force 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 of
the capillary overflow chamber with your index
finger and seat the capillary pipette holder in the
reservoir neck (see fig. 7-11).
4. Release pressure on the reservoir and remove
your finger from the overflow chamber opening.
Suction will draw the blood into the diluent in
the reservoir.
5. Squeeze the reservoir gently two or three times
to rinse the capillary tube, forcing diluent into
but not out of the overflow chamber, releasing
pressure each time to return diluent to the
reservoir. Close the upper opening with your
index finger and invert the unit several times to
mix the blood sample and the diluent. See
figure 7-12.
6. For specimen storage, cover the overflow
chamber of the capillary tube with the capillary
shield.
7-12
CAPILLARY
PIPETTE SHIELD
DIAPHRAGM
HM3f0709
Figure 7-9.—Puncturing the diaphragm of diluent with the
capillary pipette shield.
A
B
HM3f0710
Figure 7-10.—Drawing blood into the Unopette capillary
tube: A. From a finger puncture; B. From a venous blood
sample.
HM3f0711
CAPILLARY OVERFLOW
CHAMBER
Figure 7-11.—Preparing reservoir to receive blood from the
capillary tube.
