EXPERIMENT 7 Flashcards
Are dilutions made in “SERIES”
Serial Dilution
In which the (?) is further diluted
original solution
Here all dilution including or following the 1st one ARE
THE SAME
General rule for calculating the concentration of solutions obtained by the dilution in series is to
multiply the original concentration by the first dilution
Expressed as a fraction this by the (?) and so on until the desired concentration is known
second dilution
Several laboratory procedures especially serologic methods make use of a (?) in which all dilutions including all following the first one, are the same.
dilution series
Such dilutions are referred to as a serial dilution- a complete dilution series usually contains 5 or 10 tubes although any single dilution may be made directly from an (?)
undiluted specimen or substance
Serial dilution is often used to measure the
titer of an Antibody
Set of dilutions in which the (¿) is the same as each step
dilution factor
These are used to make (?) with a small number of test tubes and minimal amount of (?)
high dilution
diluent
Commonly done to determine the (?) of a particular antibody in a patient’s serum as a part of the diagnosis of a disease state
strength or titer
is the reciprocal of the last tube in which a (+) reaction is seen
Titer
The titer is written as the reciprocal of the dilution; that is the (?) is the last (+) one, the titer is written as (?)
1:60 tube
160
When collecting a sample, spin the EDTA tube for (?) in the centrifuge at (?) and remove the plasma before adding the NSS
10 mins
1500 rpm
Spin again for (?) and know the color of the saline wash on top and then wash (?) with NSS. Resuspend with additional saline uniformly. Repeat (?) or until the NSS supernatant is clear.
10 minutes
3x
3x
To make a 4% RBC suspension add (?) NSS.
500 uL to 12 mL
Note: when dispensing using a micropipette, it should be inclined and it should touch the side of the tube before dispensing, to improve accuracy of dispensing by (?) as compared to dispensing straight up.
1%
Defined as the reciprocal of the highest dilution of the patient’s serum in which the antibody is still detectable
antibody titer
Serial dilutions- perform continuous or series of dilution to a patient’s serum. Example, the original dilution of the tube is 1⁄2 followed by the next dilution 1⁄4, 1/8, 1/16 and 1/32. The antibody titer will be the last tube showing a reaction, either (?). Like in tube 4 there is still agglutination and then same as tube 1-3, but there is no agglutination in tube 5. The antibody titer is the 4th tube, a dilution factor of (?).
agglutination or hemolysis
16- antibody titer (1:16)
When the concentration is too high or less specimen is available for analysis, the original specimen may be diluted or the initial dilution further diluted
Single dilution
Dilute only once
Single dilution
The reciprocal of the dilution is the dilution factor
Single dilution
Method for determining of the concentration of substance. The greatest dilution of the sample that yields a positive result is the end point.
Serial dilution
Used for determining antibody titer
Serial dilution
Note: it also determines the strength of an antibody. The higher the titer, the stronger the antibody.
Serial dilution
For most pathogenic infections, an increase in the patient’s titer of two doubling dilutions, or from a positive result of (?) over several weeks is an indication of (?). (?) increase from the original result after several weeks.
1:8 to a positive 1:32
current infection
Twofold
