A condensation specimen that made me break out in a cold sweat

Preface

With the continuous development of science and technology, the degree of automation of inspection equipment is getting higher and higher, and when processing specimens in large quantities, it is often easy to ignore the state of
the specimens before the machine.
Condensation set is a phenomenon that is easy to affect the results of blood routine, blood type, etc.
, if not observed and corrected in time, it will produce error accidents and bring adverse consequences
.

Case history

Just after taking over at noon, the department teacher told me that there was an inpatient whose specimen was considered to be condensation set, and I would come to the window to draw blood for re-examination
later.
I checked the results for the first time, and the decrease in RBC (0.
07×1012/L) and HGB (54g/L) was obviously inconsistent, and MCH (729.
7pg) and MCHC (7037g/L) were many times better than normal, typical condensation blood collection routine results
.

Case study

Analysis of condensation set characteristics: severe condensation set, when slowly tilting the test tube, it can be found that the red blood cells are fine sand granules, and even more terrifying even completely coagulated into a huge blood clot, which needs to be shaken repeatedly to disperse
.
At the same time, there are some poorly visible condensation sets, which are mainly found
in the characteristics of the blood routine.

First of all, the principle of condensation set, which refers to the presence of cold antibodies in the blood, after the blood is isolated from the body, when the temperature drops, the cold antibody can bind to red blood cell surface antigens, so an antibody may bind several red blood cells to form agglutination
.
It can be seen in leukemia, lymphoma, Mycoplasma pneumoniae infection, etc
.
Patients with this symptom should pay attention to keeping warm to prevent blood stasis and blood circulation disorders
.

Such specimens can generally be normal after the water bath (in line with the clinic), should pay attention to take out the water bath immediately on the machine, a moment should not be delayed
.
Extremely serious, can consider centrifugation two or three times with normal saline or diluent equal amount of plasma replacement, and then water bath and then on the machine, generally can be alleviated, should pay attention to the error caused by the operation, aspiration, the amount of aspiration, the amount of addition can cause changes in the concentration of relevant indicators, centrifugation is not in place can cause platelet reduction
.

According to the above characteristics, after the patient came to the window to draw blood, I immediately went to the machine to test, RBC 2.
14×1012/L, HGB 73g/L, MCH 34.
1pg, MCHC 322g/L, the results are basically corrected, without further operations
such as warm bath or plasmapheresis.
You think that's the end of it? NO！ When reviewing the report, I took a look at the patient's diagnosis: anemia, most of these patients have blood type, I went to see the eye blood type result: AB type, according to years of work experience I feel that this result is mostly unreliable, and it has to be improved for testing
.

This is the result of the first microcolumn gel method on the machine, at that time, I thought that the result was not obvious due to insufficient suction of anemia patients, and the plate of the solid phase method was also AB type
.
It was shown that the red blood cells condensed into a mass could not pass through the gel layer of the microcolumn gel card and the carrier layer of the solid-phase plate, resulting in false-positive results
in both methods.

No way, I used normal saline to do plasma exchange, replaced it 2 times, and retested
it on the machine.
The microcolumn gel method did not change significantly or "AB", and the solid-phase method results showed O-type
.
Then I tested it again with mAb serum
.

Before plasmapheresis, only normal saline is dropped, and condensation set significantly interferes with the results

Before plasmapheresis, the mAb serum added dropwise feels like an "AB"

After plasma exchange, monoclonal antibody serum was added, and it was immediately observed that it should be an O type, but within five minutes the red blood cells began to aggregate and become "AB"

After five plasma exchanges, the microcolumn gel basically achieves the desired results

After all three methods were determined to be O-type, I was relieved to review the report
.

Summary

We occasionally encounter specimens with this condensation set in our daily work, and the blood routine can basically be avoided
by paying more attention to the relevant parameters when reviewing the report.
Although the blood group examination in our department is only a preliminary screening test, it is still necessary to pay attention to the status of the specimen before the machine, pay attention to the reagent reaction effect after the machine, and focus on the results
of the "AB" type.
For the microcolumn gel method, although we dilute red blood cells to a concentration of 0.
8%, which can avoid the situation of slight condensation set, this heavy condensation set still requires multiple plasma exchanges to obtain more ideal results
.

References

[1] CHEN Xueli.
Rare high-potency condensation collection.
GU Bing,ZHENG Minghua,CHEN Xingguo, eds.
Communication between laboratory and clinical—a case study: 200 cases.
Beijing:People's Medical Publishing House, 2011, 348-349.

[2] ZHANG Shimin.
A hemogrammetry solution for a severe condensation set sample.
Journal of Practical Laboratory Physicians.
2011, 3, 122-124.

[3] Gu Bing,Zhang Xiaoning,Huang Zhaohui,Ma Ping.
Strange disease in winter (blood samples with condensation set)[M].
Case analysis of clinical test results.

[4] XU Wenrong, WANG Jianzhong.
Clinical Hematology and Laboratory[M].
4 Edition, Beijing:People's Medical Publishing House.

[5] GAO Fuyun.
Analysis and treatment of interference factors for microcolumn gel cassette blood group identification.
Diet Health.
2019,6(3),246.