Treatment of a case of autoimmune hemolytic anemia with strong cold agglutination

foreword

Foreword Foreword

Cold agglomeration is a problem that we often encounter in our work.
It will make RBC and HCT falsely lower than the true value, and MCH and MCHC falsely increase than the true value
.

This results in inaccurate blood routine test results and wrong guidance for clinical practice

case after

case by case by case

The child, female, 11 years old and 2 months old, complained of pale complexion for more than 20 days and abdominal pain for three days.
She was diagnosed with "moderate anemia" and was admitted to the hospital
.

The blood routine results are shown in Figure 1, and the blood status is shown in Figure 2

diagnosis

Figure 1 Indicates cold agglomeration, and obvious cold agglomeration can be seen in the specimen

Figure 1 Indicates cold agglomeration, and obvious cold agglomeration can be seen in the specimen

Figure 2 Blood routine specimens with fine sand-like particles agglutination

Figure 2 Blood routine specimens with fine sand-like particles agglutination

Take immediate action:

Take immediate action: Take immediate action:

Warm bath method: After the specimen was incubated at 37.
5 °C for 1 hour, the parameters such as HCT and MCHC did not change much
.

The result is shown in Figure 3

37.

Figure 3 The specimen was incubated at 37.
5°C for 1 hour

Figure 3 The specimen was incubated at 37.
5°C for 1 hour

Then take the second method, plasma exchange method:

The second method was adopted, plasma exchange method: The second method was adopted, plasma exchange method:

Centrifuge the blood routine samples at low speed for 3-5 minutes, slowly remove the upper plasma with a pipette and discard, and record the amount discarded, then add an equal amount of 37°C warmed saline, mix well, centrifuge again, and discard The supernatant was washed three times according to this method, and finally an equal amount of 37°C warm bath physiological saline was added, and the mixture was mixed and measured immediately
.

The blood is washed with normal saline as shown in Figure 4, and the measurement results are shown in Figure 5

3-5

Figure 4: State after washing with saline

Figure 4: State after washing with saline

Figure 5 Measurement results after blood washing

Figure 5 Measurement results after blood washing

3.
The method of using the RET channel for cold-aggregation sample processing:

3.
The method of using the RET channel for cold-aggregation sample processing:

Viewing the RET-related parameters of the specimen, you can get the RBC-O result.
The RBC-O parameter is the red blood cell result of the RET channel.
Because the nucleic acid fluorescence staining method is more accurate than the RBC result of the impedance channel, the RBC-O result is: 1.
22 ×1012/L
.

Figure 6

Figure 6 RET related parameters

Figure 6 RET related parameters

In the Service interface, we can get the R-MFV parameter, R-MFV (RBC-mostfrequent volume), which is the red blood cell volume with the highest frequency in the detection, which is used to compare the MCV.
There is no difference between the two in statistical
.

R-MFV: 145.

statistics

Figure 7 R-MFV parameters on the Service interface

Figure 7 R-MFV parameters on the Service interface

In this way, we can obtain relatively accurate RBC results and MCV results.
Since cold condensation has little effect on HGB, the HGB results refer to the measurement results and use the calculation formula:

MCV (mean red blood cell volume) = HCT/RBC

MCH (mean corpuscular hemoglobin content) = HGB/RBC

MCHC (mean corpuscular hemoglobin concentration) = HGB/HCT

Calculated HCT is 17.
8%, MCH is 40.
98pg, MCHC is 280.
9g/L

According to the above three methods, the parameters are compared in Table 1 below
.

Table 1 Comparison between various approaches

Table 1 Comparison between various approaches

Note: Parameters such as RBC-0 and R-MFV will only appear in Ret mode

Note: Parameters such as RBC-0 and R-MFV will only appear in Ret mode

The numerical units of each analysis item are: RBC is ×1012/L; HCT is %; MCV is fl; MCH is pg; MCHC is g/L;

I thought I could send the report directly, but the engineer happened to be there that day, so I asked him for advice, and then he introduced another algorithm: RBC-He is used as the RET channel to measure the average erythrocyte hemoglobin content, which has a good correlation with MCH after statistics ( 1000 non-cold agglomerated samples were counted to detect the data of CBC+RET, and the correlation between RBC-He and MCH was obtained), and RBC-He was 0.
9201 times that of MCH
.

Correcting RBC-He can get more accurate MCH results.

As shown in the above case, the RBC-He is 36.
7pg.
Through the conversion formula, the MCH is 40.
78pg, which is not much different from the MCH40.
98pg converted by the above method.
Therefore, if the RBC-He is adjusted to the same level as the MCH, the RBC can be used directly.
-He replaces MCH
.

case analysis

case analysis

The RET detection channel needs to increase the staining temperature to 41 °C, which can depolymerize red blood cells in a short time, and obtain the RBC-O result.
The RBC-O parameter is the red blood cell result of the RET channel.
The RBC results of the impedance channel are more accurate, and then the corresponding red blood cell-related parameter results are obtained according to the calculation formula
.

Of course, based on the factors that cause erythrocyte cold agglutination, warm bath or plasma exchange is the standard method to correct erythrocyte cold agglomeration.
In the case of partial loss of components, the RET channel research parameter calculation method can be considered, which can not only improve the test efficiency, but also shorten the TAT time of outpatient and emergency specimens
.

The cold agglomeration cases encountered in normal work can basically be corrected by warm bath or plasma exchange, but this patient did not get good results through these two methods.
After follow-up examination, it was found that this was a case of autoimmune hemolytic disease.
Anemia secondary to mycoplasma infection in patients
.

immune infection

Cold agglutination of erythrocytes is a phenomenon, and the degree of cold agglutination is positively correlated with the cold agglutination titer [2]
.

Cold agglutinins (CAs) are erythrocyte autoantibodies, mainly of IgM type, and a small part of IgG and IgA types.

Factors that cause red blood cell cold agglomeration include:

1. Mycoplasma infection
   .
   
2. Infectious mononucleosis, severe anemia, myeloma, liver cirrhosis and other diseases can also have positive reactions
   .
   
3. Patients with autoimmune hemolytic anemia may have secondary mycoplasma pneumonia with positive cold agglutinin titers (in this case)
   .
   
4. Affected by the external ambient temperature, autumn and winter are the seasons with high occurrence of cold condensation
   .
   

Mycoplasma infection
.

Infectious mononucleosis, severe anemia, myeloma, liver cirrhosis and other diseases can also have positive reactions
.

Patients with autoimmune hemolytic anemia may have secondary mycoplasma pneumonia with positive cold agglutinin titers (in this case)
.

Affected by the external ambient temperature, autumn and winter are the seasons with high occurrence of cold condensation
.

Summarize

summary summary

Red blood cell cold agglutination is a reversible process.
In blood cell analysis, we found that the red blood cells of some patients are prone to cold agglutination.
When the upper limit is 20g/L, it is required to check whether the specimen has lipidemia, hemolysis, agglutination and spherocytes
.

According to this rule, cold agglomeration of specimens or other abnormal specimens can be found
.
Cold agglomeration will make RBC and HCT falsely lower than the true value, and MCH and MCHC falsely increase than the true value
.
This results in inaccurate blood routine test results and wrong guidance for clinical practice
.
Therefore, for the specimens with MCHC>380, more attention should be paid to the inspection colleagues to avoid clinical misdiagnosis
.

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