Haematocrit Measurement; Haematocrit Capillaries - Overview; Filling Of The Haematocrit Capillaries; Sealing And Centrifugation Of The Haematocrit Capillaries - Hettich HAEMATOKRIT 210 Operating Instructions Manual

14

Haematocrit measurement

14.1

Haematocrit capillaries - Overview

Standard capillary tubes, Order No.: 2074
The classical heparinized haematocrit capillary tube made of glass. Tried and tested for years.
Mylar-reinforced capillary tubes, Order No.: 1072
The heparinized glass capillary is coated with plastic. Should such a capillary break the glass splinters are retained in
this coating. This means that the risk of injury for the user is reduced.
Self-sealing capillary tubes, Order No. 1071
These capillary tubes, which are also heparinized, no longer need to be sealed. They are already equipped with a
seal. At first, the seal material is air-permeable so that the capillary can be filled. The seal will only become
impermeable when it comes into contact with blood. Therefore, there will be no leaks during centrifugation.
14.2

Filling of the haematocrit capillaries

The capillaries have different volumes according to type.
The following are the exact data:
Capillary:
Order No.:
Total volume without seal (µl):
Internal diameter (mm):
Overall length (mm)
Therefore, more blood is needed for the capillaries No. 1072 and 1071 to be filled. The dimensions, however, are still
in compliance with the requirements of DIN 12846 (standard for haematocrit capillaries) and the accuracy of the
haematocrit values is not affected.
For the haematocrit measurement the capillaries are always filled up to ≈ 75%:
Capillary:
Order No.:
Volume when filled up to 75%(µl)
14.3

Sealing and centrifugation of the haematocrit capillaries

14.3.1

Standard capillary tubes, Order No.: 2074, and mylar-reinforced capillary tubes, Order No.: 1072

1. When filling the capillary ensure that the end of the capillary opposite the filler opening remains dry.
2. Seal at the dry end of the capillary:
Insert the capillary tube vertically into the seal up to the point where the end of the capillary touches the bottom
of the seal plate.
Slightly tilt the capillary tube to the side and remove it from the seal.
3. Place the capillary tubes with the lute side facing outwards in the haematocrit rotor and apply the rotor lid and
click into place.
4. Centrifuge.
5. Determine the haematocrit value.
Standard Mylar-reinforced
2074 1072
49.6 74.9
0.92 1.12
75 75
Standard Mylar-reinforced
2074 1072
37.2 56.2
EN
Self-sealing
1071
74.9
1.12
75
Self-sealing
1071
56.2
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