The Influence of Hemolyzed Specimen on Biochemical Items and Handling Methods

Today an intern asked me , " Why are hemolyzed specimens rejected ?" I replied : " Hemolysis will interfere with the response of many test items , resulting in erroneous results
.

" Then asked : " Which items in our biochemistry will be affected ?" He also asked : " How can I avoid hemolysis of the specimen ? Are all hemolyzed specimens rejected ?"

Today an intern asked me , " Why are hemolyzed specimens rejected ?" I replied : " Hemolysis will interfere with the response of many test items , resulting in erroneous results

01 01

Why are hemolyzed specimens rejected ?

Why are hemolyzed specimens rejected Why are hemolyzed specimens rejected ?
?

Specimen hemolysis is one of the most common interference and influencing factors in clinical biochemical tests
.

After hemolysis, most biochemical reactions will be affected , resulting in inaccurate test results , which cannot objectively and truly reflect the patient's physical condition at that time

Specimen hemolysis is one of the most common interference and influencing factors in clinical biochemical tests

02 02

Which biochemical items will be affected and their impact mechanism ?

Which biochemical items will be affected and its impact mechanism ? Which biochemical items will be affected and its impact mechanism ?

Items with high results

Items with high results Items with high results

(1) Aspartate aminotransferase (AST):The content of AST in red blood cells is nearly 40 times higher than that in plasma , so AST can be increased during hemolysis .

(1) Aspartate aminotransferase (AST):The content of AST in red blood cells is nearly 40 times higher than that in plasma , so AST can be increased during hemolysis .

(2) Alanine aminotransferase (ALT): The content of ALT in red blood cells is about 7 times higher than that in plasma , so ALT can also increase after hemolysis .
Compared with AST , it can be seen that hemolysis has little effect on this index .

(3) Lactate dehydrogenase (LDH) and α - hydrobutyrate decarboxylase (α-HBDH): The content of LDH in erythrocytes is 180 times higher than that in serum , even small hemolysis will lead to higher results .
The activity of LDH is basically reflected by α-HBDH , and the two will increase synchronously during hemolysis .

(4) Phosphocreatine kinase (CK) and creatine kinase isoenzyme (CK-MB): the presence of adenylate kinase (AK) in erythrocytes produces creatine and creatine triphosphate and adenosine diphosphate (ADP) in red blood cells.

The reaction of adenosine triphosphate (ATP) has a catalytic effect , and the ATP generated during the reaction will increase the activity of CK , which will lead to higher results .
The same isoenzyme CK-MB will also increase .

(4) Phosphocreatine kinase (CK) and creatine kinase isoenzyme (CK-MB): the presence of adenylate kinase (AK) in erythrocytes produces creatine and creatine triphosphate and adenosine diphosphate (ADP) in red blood cells.
The reaction of adenosine triphosphate (ATP) has a catalytic effect , and the ATP generated during the reaction will increase the activity of CK , which will lead to higher results .
The same isoenzyme CK-MB will also increase .

(5) Potassium (K): The concentration of potassium ions in red blood cells is more than 30 times higher than that in plasma , and K will increase significantly after hemolysis .

(5) Potassium (K): The concentration of potassium ions in red blood cells is more than 30 times higher than that in plasma , and K will increase significantly after hemolysis .

(6) Total protein (TP): generally choose the biuret method to measure , the main wavelength of measurement is 540nm

(7) Cholinesterase (CHE): The true CHE escaped from the red blood cells during hemolysis , resulting in a false increase in serum CHE results .

Items with low results Items with low results

(1) γ -glutamyltransferase (γ-GT): When the specimen is hemolyzed , it will cause the activity of γ-GT to decrease , which will lead to the decrease of the measurement result .

(1) γ -glutamyltransferase (γ-GT): When the specimen is hemolyzed , it will cause the activity of γ-GT to decrease , which will lead to the decrease of the measurement result .

(2) Alkaline phosphatase (ALP): Hemolysis of the same specimen will lead to a decrease in ALP activity , resulting in a pseudo -lowered ALP level
.

(2) Alkaline phosphatase (ALP): Hemolysis of the same specimen will lead to a decrease in ALP activity , resulting in a pseudo -lowered ALP level
.

(3) Glucose (GLU): The serum is diluted after hemolysis of the specimen and the reductive coenzyme released after the rupture of red blood cells neutralizes part of the intermediate product H2O2 in the reaction process, which reduces the concentration of the final product of the reaction quinone dye , which affects two aspects.
A combination of factors resulted in a low Glu measured value
.

(3) Glucose (GLU): The serum is diluted after hemolysis of the specimen and the reductive coenzyme released after the rupture of red blood cells neutralizes part of the intermediate product H2O2 in the reaction process, which reduces the concentration of the final product of the reaction quinone dye , which affects two aspects.
A combination of factors resulted in a low Glu measured value
.

Figure 1 shows the test results of hemolysis of the patient's specimen , and Figure 2 shows the test results of the same patient's specimens that were found to be hemolyzed on the same day and then redrawn , but no hemolysis occurred
.
It can be seen from the following two pictures that AST , LDH , α-HBDH , CK , CK-MB , TP and CHE were significantly increased before and after hemolysis , while K and ALT were significantly increased , while ALP and γ-GT did not change significantly
.
This may be related to the degree of hemolysis of the specimen
.

Figure 1 shows the test results of hemolysis of the patient's specimen , and Figure 2 shows the test results of the same patient's specimens that were found to be hemolyzed on the same day and then redrawn , but no hemolysis occurred
.
It can be seen from the following two pictures that AST , LDH , α-HBDH , CK , CK-MB , TP and CHE were significantly increased before and after hemolysis , while K and ALT were significantly increased , while ALP and γ-GT did not change significantly
.
This may be related to the degree of hemolysis of the specimen
.

Figure 1

Figure 1

Figure 2

Figure 2

The mechanism of specimen hemolysis affecting biochemical reaction items coexists and interacts , which makes the affected test items more complicated .
Therefore , strict control of specimen hemolysis is an important aspect to ensure the test quality
.

The mechanism of specimen hemolysis affecting biochemical reaction items coexists and interacts , which makes the affected test items more complicated .
Therefore , strict control of specimen hemolysis is an important aspect to ensure the test quality
.

03

03 03

How to avoid specimen hemolysis ?

How to avoid specimen hemolysis ?
How to avoid specimen hemolysis ?

Obtaining a non-hemolyzed sample is determined by many factors
.
As much as possible, allow the blood to flow as smoothly as possible from the vessel to the tube when collecting the specimen
.
When drawing blood with a syringe, apply very little force to draw the blood into the barrel
.
When the needle of the syringe is suitable , the syringe plunger can be gently pulled back to control the slow flow of blood into the barrel
.
The same process is used when injecting blood into a test tube with a syringe
.
Vacuum blood collection tube is better than syringe blood collection because of maintaining proper pressure .
In addition, the conditions and methods of specimen transportation, storage, centrifugation, and supernatant separation should also be mastered .

Obtaining a non-hemolyzed sample is determined by many factors
.
As much as possible, allow the blood to flow as smoothly as possible from the vessel to the tube when collecting the specimen
.
When drawing blood with a syringe, apply very little force to draw the blood into the barrel
.
The needle of the syringe fits into the blood vessel , and the plunger of the syringe is pulled back gently to control the slow flow of blood into the barrel
.
The same process is used when injecting blood into a test tube with a syringe
.
Vacuum blood collection tube is better than syringe blood collection because of maintaining proper pressure .
In addition, the conditions and methods of specimen transportation, storage, centrifugation, and supernatant separation should also be mastered .

04

04 04

Common causes of hemolysis in biochemical specimens are :

Common causes of hemolysis in biochemical specimens are :

1.
The inside of the syringe or container is not clean
.

1.
The inside of the syringe or container is not clean
.

2.
The needle used when drawing blood is too small, the force for drawing blood is too large, the tourniquet is used for a long time, and too much foam is generated
.
When tying the tourniquet, it should not be too tight , and it should not exceed 1 minute
.

2.
The needle used when drawing blood is too small, the force for drawing blood is too large, the tourniquet is used for a long time, and too much foam is generated
.
When tying the tourniquet, it should not be too tight , and it should not exceed 1 minute
.

3.
Directly inject the blood into the container without removing the needle after the blood is drawn
.

3.
Directly inject the blood into the container without removing the needle after the blood is drawn
.

4.
The glass tube is broken during centrifugation,
etc.

4.
The glass tube is broken during centrifugation,
etc.

05

05 05

How does a laboratory test a sample for hemolysis ?

How does the laboratory test the sample for hemolysis ? How does the laboratory test the sample for hemolysis ?

Under the current detection conditions , the automatic biochemical analyzer can automatically detect the hemolysis index quickly and reliably , determine the degree of hemolysis by the hemolysis index of the sample , and transmit the detection results to the LIS system
.

Under the current detection conditions , the automatic biochemical analyzer can automatically detect the hemolysis index quickly and reliably , determine the degree of hemolysis by the hemolysis index of the sample , and transmit the detection results to the LIS system
.

06

06 06

When does hemolysis count as hemolysis ? How do we deal with it ?

When does hemolysis count as hemolysis ? How do we deal with it ? When does hemolysis count as hemolysis ? How do we deal with it ?

Manufacturers of biochemical reagents will provide instructions on the interference of hemoglobin concentration on test items for different reagents , but they do not point out the correlation between the amount of overflowing hemoglobin and the change of results
.
This requires us to try not to use hemolytic specimens unless absolutely necessary .
If it is absolutely necessary , the hemolysis of the specimen must also be indicated on the report sheet , and the degree of hemolysis should be indicated and communicated with the clinician .  

Manufacturers of biochemical reagents will provide instructions on the interference of hemoglobin concentration on test items for different reagents , but they do not point out the correlation between the amount of overflowing hemoglobin and the change of results
.
This requires us to try not to use hemolytic specimens unless absolutely necessary .
If it is absolutely necessary , the hemolysis of the specimen must also be indicated on the report sheet , and the degree of hemolysis should be indicated and communicated with the clinician .
 

07

07 07

Not all hemolyzed specimens are rejected

Not all hemolyzed specimens are rejected Not all hemolysed specimens are rejected

Caution must be exercised when directly rejecting hemolyzed samples , because some hemolysis is not due to human-induced hemolysis in vitro , but in vivo due to the patient's own disease .
For example, patients with hereditary spherocytosis, G-6-PD deficiency, thalassemia / thalassemia, autoimmune hemolytic anemia, and paroxysmal nocturnal hemoglobinuria can show in vivo hemolysis .
Such patients also need to do biochemical tests , we must fully communicate with the clinician , indicate the degree of hemolysis on the test sheet and issue a test report .

Caution must be exercised when directly rejecting hemolyzed samples , because some hemolysis is not due to human-induced hemolysis in vitro , but in vivo due to the patient's own disease .
For example, patients with hereditary spherocytosis, G-6-PD deficiency, thalassemia / thalassemia, autoimmune hemolytic anemia, and paroxysmal nocturnal hemoglobinuria can show in vivo hemolysis .
Such patients also need to do biochemical tests for immunity .
We must fully communicate with clinicians , indicate the degree of hemolysis on the test sheet and issue a test report .
leave a message here