An example of thinking that blood types do not match positive and negative stereotypes

【Introduction】

When it comes to blood group identification, everyone may habitually think that it is nothing more than screening the ABO blood group system, but in fact, the International Society for Blood Transfusion (ISBT) has classified the 339 red blood cell blood group antigens that have been discovered and confirmed so far into 33 blood group systems (a total of 297 antigens), 7 blood group collections (a total of 18 antigens) and 2 blood group series (low-frequency antigen 700 series has 18 antigens, high-frequency antigen 901 series has 6 antigens).

Naturally, we will inevitably encounter positive and negative stereotypes in our work, and then discover other blood group systems
.

【Case History】

On April 28, the automatic blood group analyzer could not interpret the blood group results of a patient, as shown in Figure 1, the instrument took pictures as a reverse photo, when we viewed the interpretation results on the instrument operation interface, the right side was positive and the left side was reverse typing
.
As can be seen from the figure, the positive stereotype is type B, Rh(+), the inverse type is O, and the positive and negative stereotypes are inconsistent?

Figure 1

Check the reagent card and ABO anti-stereotyped red blood cell suspension reagent are all within the validity period, the blood group card has been centrifuged 3 times at room temperature before testing, and the anti-stereotyped red blood cell suspension reagent is fresh and does not change color
.
Therefore, according to the hypothesis method, we generally assume that the positive training is wrong and the reverse training is correct, as shown in Figure 2
.
According to the instructions of the reagent, prepare 3% of the patient's erythrocyte suspension concentration, wash the normal saline repeatedly 3 to 4 times (the purpose is to clean the excess impurities or allergenic components on the surface of the red blood cells thoroughly), add the red suspension to the column agglutination card 1 to 4 wells, incubate for 10 to 15 minutes (the purpose is to exclude condensation set), and still be type
B after centrifugation.

Figure 2

Initially determine that the positive stereotype is correct, and secondly, assuming that the positive stereotype is correct and the anti-stereotype is wrong, that is, there is a problem with the plasma, irregular antibodies? Some protein interference? As shown in Figure 3
.

Figure 3

Combined with patient information, female, 52 years old, clinical diagnosis: decompensated liver cirrhosis after hepatitis B, its blood routine results are shown in Figure 4, the three lines are reduced, and the historical results are not much
different from one year ago.

Figure 4

Comprehensive consideration, let's start with irregular antibody investigation, the so-called irregular antibody refers to other blood group antibodies other than anti-A and anti-B, also known as "accidental antibodies"
.
Take irregular antibody detection reagents O1, O2, O3 red blood cells and the patient's plasma and add equal amounts to the card, pre-warm for 10 minutes and centrifuge, as shown in Figure 5, O1 and O3 red blood cells are positive
.
Control reagent antigen profile, the following antigens may be present: C and e antigens in the Rh blood group system, N antigens in the MNS blood group system, Lea antigen in the Lewis blood group system, as shown in Figure 6
.

Figure 5

Figure 6

The test was continued using the Rh system typing detection card (gel method), and the red blood cell suspension of patients with a concentration of 3% was added to each column, and the microcolumn was flicked to mix well, and centrifuged for 5 minutes, as shown in Figure 7, anti-c, anti-D, and anti-E wells were positive
.
According to the judgment table as shown in Figure 8, it can be seen that the patient's Rh blood group classification result is: ccDEE
.

Figure 7

Figure 8

【Case Study】

(1) The patient's Rh blood group classification results are: ccDEE, and the Rh blood group system is clinically important only to the ABO blood group system, Rh blood group system is very complex, containing the largest number of antigens, a total of 54, but the most important and common clinical only 5 antigens, namely D, C, C, E
, E.
At present, we encounter irregular antibody screening positive patients, generally continue to screen the Rh blood group system first, if there is no problem with the Rh blood group system, we will continue to screen other blood group system types
.
In this case, due to the lack of MNS and Lewis blood group system typing reagent cards in primary hospitals, no further testing was carried out, which was slightly inadequate
.

(2) In this case, the positive and negative stereotyping of the patient does not match (column agglutination method), and the use of test-tube saline method inverse stereotyping is type B, considering the different media of these two methodologies, the column agglutination method detects IgG antibodies, and the test-tube saline method detects IgM antibodies
.
Therefore, do not be anxious because the test tube saline method is anti-stereotyped as type B, and report that both positive and negative stereotyping are type B, which is easy to mislead clinical and blood transfusion colleagues
.
When the positive training is correct and the reverse training is in doubt, we generally report the positive training first, and explain the negative training in the remarks column to be reviewed
.

(3) When the patient has inconsistent positive and negative stereotypes, we exclude the possibility of weakened antibody titer according to age and clinical diagnosis, because if the antibody titer is weakened, its countertyping should be AB type (that is, red blood cell suspension sinks at the bottom of the column).

The patient is decompensated with cirrhosis and long-term chronic disease, so it can be seen from the results of his blood routine one year ago that the basic difference is not much, excluding autoantibodies and a large amount of infusion
.
Looking at the biochemical results, as shown in Figure 9, globulin 27.
8g/L, the influence
of M protein can also be ruled out for the time being.

Figure 9

Therefore, in the face of positive and negative stereotypes inconsistent, it is necessary to combine the patient's examination to basically exclude which factors, and then focus on what factors will exist, do not encounter positive and negative stereotypes inconsistent, immediately start irregular antibody screening and other examinations
.
In our previous work, we have learned a lesson, once a patient due to a large amount of postoperative rehydration, plasma was diluted, there was a positive and negative stereotyping inconsistency, immediately screened for irregular antibodies but found nothing, and finally inquired about the doctor's advice to know that there was a large history
of infusion before blood collection.

【Summary】

Blood transfusion is related to life safety, so blood group identification is no small matter, once there is a blood transfusion reaction will start the reverse check procedure, so the blood group identification in the work must be tested in accordance with the operating procedures, not lazy and slack
.
In addition, when we encounter inconsistent positive and negative stereotyping and agglutination on the primary and secondary sides, we need to calmly analyze the reasons to find the problem, and then screen the correct and suitable blood source
for the patient.

【References】

[1] ZHANG Yinze,XU Hua,ZHOU Huayou.
Principle and detection strategy of red blood cell blood group[M]Beijing:People's Publishing House,2014:2

[2] Hu Lihua, Clinical transfusion testing technology[M].
Beijing:People's Medical Publishing House,2015:10,S18-22