To see is to believe? A case of normal erythrocyte sedimentation results lead to thinking!

Case passed

When I was working on Sunday night, a result of an osteomyemaposition of 2mm/h made me feel bad
.

Fig.

Since it is all seen as believing, it is not wrong
.

We all know that anemia and many disease states can lead to accelerated erythrocyte sedimentation, but why is his result so normal? Can this result be published with the note "results verified"?

Case studies

Visually, the specimen does belong to the traits of a pronounced anemia sample, and it is reasonable that red blood cells should drop quickly when anemia
.

After centrifugation, the appearance is actually not obvious abnormality, but the height of the red blood cell layer seems to be a little too low (Figure 2
).

Fig.

Just when there was no way out, it was also very strange
to find that the biochemical results of the patient came out.

Figure 3 The patient had two biochemical results in the same day

Faced with such results, experience tells us that the specimen may have been diluted
.

While waiting for the specimen to be re-delivered, we found that the patient had also been tested for troponin
at the same time.

Fig.

The result we realized was very likely to be diluted, otherwise it would not be such a coincidence
.

When the patient re-drew blood and sent it, the results of the routine biochemical review were not much different from the daytime results, and the blood K and Ca also returned to 4.

When we report such results to the clinic, we hope that they will recall whether there is anything wrong with it, but still do not get a positive answer
.

It is reasonable to say that the viscosity of plasma decreases after dilution, at which time the red blood cells are subjected to reduced resistance and therefore accelerate the sinking
.

Most of the plasma is sucked out of the selected specimen, and an equal amount of normal saline is added before measurement
.

Review the influencing factors of erythrocyte sedimentation, more important plasma factors (including plasma protein composition and proportion, plasma cholesterol content, etc.

In plasma, the strongest substance for the formation of erythrocyte rebellies is fibrinogen, followed by γ-globulins and abnormally clonal immunoglobulins, and then α globulins, β globulins, cholesterol and triglycerides
.
When the blood is diluted, the concentration of the components mentioned above that accelerate erythrocyte sedimentation decreases
.

In terms of red blood cells, although the number of red blood cells decreases and the ESR sedimentation is accelerated, when the number is too small, it is not conducive to the formation of money-like aggregation, but it slows down
the ESR.
But I don't think that's the main reason, after all, in the previous simulation test, an equal amount of saline
was added.

That is to say, the number of red blood cells after replacement is almost the same as that of the original specimen, but all of them have a false decrease
.
In addition, the size of red blood cells is uneven, and the surface area of spherical and sickle erythrocytosis decreases, which is not conducive to the aggregation of
money.
In the past, I have found that after plasma exchange with normal saline, the morphology of red blood cells changes significantly (Figure 5), and the uneven size and spherical trend may be related
to changes in factors such as pH and osmotic pressure of the environment.

In summary, I speculate that the seropostillative slowdown of erythrocyte after dilution of normal saline is most likely related
to changes in plasma composition and red blood cell morphology resulting in the ineffective formation of colossal aggregation between red blood cells.

Fig.
5 The same blood routine specimen before saline dilution (left) and after dilution (right)

Summary

The key to improving the ability to identify and process abnormal results lies in continuous learning and strengthening internal strength
.
In clinical work, most of the test errors come from the quality of the sample before the analysis, which determines the accuracy of the results
.

In the identification of wrong samples or results, in addition to some routine skills, such as encountering thrombocytopenia to check whether there are clots or aggregation, encountering high potassium and low calcium results to think of anticoagulant contamination, etc.
, but also pay attention to the connection and logic between the results, learn horizontal (historical comparison) and longitudinal (the same project results in one day) comparison, which is the high-order ability
that must be mastered by the audit and inspection report.

The existence of any indicator is not isolated, and there is a direct or indirect relationship
with other indicators.
In addition, although the indicators will change with the development of the disease and treatment, some indicators are not prone to sharp fluctuations
in a short period of time.
Understanding and mastering the relationship between indicators, dialectically analyzing the results of indicators, helps us to peel back the cocoon and see the day
.
And once we lack this ability, it is easy for us to be confused by appearances, fail to discover the essence of the problem, and regard review as the truth
to solve all problems.

This case happened to occur in September, which is also the entry time of new nurses, which is the high incidence of unqualified samples every year
.
The occurrence of unqualified specimens is inevitable, and the key is how to effectively identify it and avoid publishing incorrect results that affect the patient's diagnosis and treatment
.

In addition to regular training, some audit correlation prompts should be set up on the Lis side to help block such suspicious specimens
.
If the blood count results are looked at alone, the patient has major upper gastrointestinal bleeding, even if the short-term change in HGB is large
.
Even if the clinical communication is carefully carried out, due to the clinical denial of irregular blood drawing, then this result will definitely be reported directly
.
So what to do? The best way to do this is to synthesize the results in relation to other results, such as looking at other specimen traits and results such as biochemistry or erythrocyte sedimentation in the same period for abnormal performance
.
Through this comprehensive analysis, the risk
of medical errors caused by unqualified samples can be minimized.

References

Liu Chengyu,Luo Chunli.
Clinical Laboratory Basics[M].
5 v.
Beijing:People's Medical Publishing House,2012.
]