What should I do if the red blood cell agglutination cannot be corrected by the warm bath?

Preface

Preface

Red blood cell agglutination can lead to abnormal blood routine-related results.
The agglutination we encounter in our daily work is mostly cold agglutination, which can be effectively corrected by warm baths
.

However, we will also encounter individual red blood cell agglutination specimens, which cannot be effectively resolved by warm baths

Case history

Case history

In the morning of 2021.
10.
15, the author found an abnormal result of an inpatient (female, 34 years old, admitted to the hospital with liver injury) during the blood routine review process, as follows:

The results showed that the RBC count was low, the MCH and MCHC were abnormally increased, and the RDW-SD and RDW-CV parameters were not displayed (indicating abnormal red blood cell histogram), so check the red blood cell histogram and alarm information
.

It is found that the right part of the histogram has a bow phenomenon, which indicates the presence of a large red blood cell group, and the alarm message prompts: red blood cell agglutination? Find out the specimen and observe the properties of the specimen.

Red blood cell agglutination? Find out the specimen and observe the properties of the specimen.

So the specimens were tested after being heated at 37°C for 30 minutes, and the results were as follows:

It can be seen from the results that although MCH and MCHC have decreased, the red blood cell histogram is still abnormal, and red blood cell agglutination has not been corrected
.

In order to obtain satisfactory results, the specimen was placed in a 37°C warm bath for 1 hour.

The red blood cell histogram is still abnormal, and there is little change in the temperature bath for 1 hour compared with half an hour
.

In order to provide the patient with accurate results as soon as possible, the patient was contacted to come to the laboratory for on-site blood sampling, and the test was performed immediately after the sampling.

The red blood cell histogram returned to normal, RBC and HCT increased, and MCH, MCHC, and MCV all decreased significantly.
The results are credible
.

Remark "This specimen has agglutination of red blood cells, this is the result of on-site blood draw" and issue a report

case analysis

case analysis

The phenomenon of agglutination has a great influence on blood routine results, and can cause serious errors in the results of multiple parameters.
In particular, the ratio of RBC and HGB is seriously inconsistent, HCT is seriously low, and MCV, MCH, and MCHC are abnormally increased
.

The agglutination phenomenon not only affects RBC, but also has a certain agglutination effect on white blood cells and platelets.

Most of the erythrocyte aggregation phenomena encountered in our daily inspection work are caused by cold agglutinin, which can be corrected by a 37℃ warm bath
.

Condensation refers to the phenomenon of red blood cells condensing into clumps in a cold environment caused by autoantibodies

Generally, condensation reaction occurs below 30°C, and is strongest at 0-4°C, and red blood cell agglutination is the most obvious, but the agglutination can disappear when the temperature rises
.

Cold agglutination mainly occurs in patients with cold agglutinin disease.
In addition, patients with mycoplasma infection, certain viral infections, lymphatic proliferative diseases, macroglobulinemia, and multiple myeloma may also occur in patients with cold agglutination
.

In this case, the red blood cell agglutination specimen was not effectively corrected by the warm bath.
We finally chose to draw blood on the spot and perform timely detection before the agglutination occurred, and the correct result was obtained
.
It means that this specimen is most likely not a cold set.
Inquiring about other examination results of the patient, it was found that immunoglobulin-related tests were also performed on the same day, suggesting an abnormal increase in IgG
.

This found the answer to the question
.
IgG is a thermoreactive antibody, and the optimal temperature for reacting with red blood cells is 37°C.
Therefore, a 37°C warm bath cannot solve the red blood cell agglutination caused by IgG, but may increase it
.

In addition, because the IgM class of antibodies in the agglutination reaction is hundreds of times stronger than the IgG class, the abnormal increase in MCH and MCHC caused by IgG warm antibody-type red blood cell agglutination is not as significant as the condensation caused by IgM.
In this case The specimen was tested for MCH 49.
0 pg and MCHC 413g/L for the first time, and the increase in MCH caused by condensation can reach hundreds and thousands of MCHC
.
Therefore, special attention should be paid to red blood cell agglutination caused by warm antibody IgG, and a comprehensive judgment must be combined with the red blood cell histogram
.

When we process the condensed collection specimens through the warm bath, if the MCHC after the warm bath is less than 380g/L, it is usually considered that the condensate collection has been effectively corrected
.
However, for the agglutination of red blood cells caused by thermoreactive autoantibodies, MCHC<380g/L cannot be regarded as agglutination corrected
.
Although the MCHC of the specimen in this case fell below 380g/L after the 37°C warm bath, the red blood cell histogram was still abnormal, so the agglutination could not be considered corrected.
After re-drawing the blood, the true value of MCHC was 330g/L
.

The laboratory shall establish a laboratory suitable for this laboratory in accordance with Article 13 of the re-examination rules recommended by the International Committee for Standardization in Hematology.
“When MCHC exceeds the upper limit of normal 20g/L, it is required to check whether the specimen has lipemia, hemolysis, agglutination, and spherical red blood cells.
” The re-examination rules on agglutination
.
And when sending the test report, note that there is agglutination of red blood cells, and remind the doctor to pay attention (because the agglutination of the specimen is helpful for the diagnosis of certain diseases)
.
After follow-up, this patient was finally diagnosed with systemic lupus erythematosus and was transferred to the rheumatology department for treatment
.

 

Summarize

Summarize

As an inspection worker, red blood cell agglutination should be discovered in time and interference should be eliminated in daily work
.
When reviewing the results, special attention should be paid to RBC, HCT, MCV, MCH, MCHC and other indicators that are greatly affected by red blood cells.
Observe whether the red blood cell histogram is abnormal.
At the same time, pay attention to the specimens, such as the accumulation of fine sand on the test tube wall.
The possibility of agglutination should be considered
.
For the agglutination of red blood cells caused by temperature-reactive antibodies, warm baths cannot be effectively corrected.
At this time, on-site blood sampling is a good choice for timely detection
.

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