Differences in blood collection results in bacterial and viral infections (white blood cell count, fractions, CRP)

This content includes a lot of grammatical and vocabulary errors.Please cut me some slack from Japan.

Bacteria and Viruses. The two major infectious causes as you know. The difference of symptoms has been briefly described before in ☆Link: How to recognize a case of Cases☆, so this time I will describe the difference of blood sampling results. In this article, I will discuss the differences in the results of blood sampling.

Bacteria infection

Bacteria cause an explosion in the white blood cell count. Normally, the white blood cell count is about 5000-8000. but during a bacterial infection, the white blood cell count increases by a factor of 20,000 to 30,000, or 4 to 5 times. but when infected with bacteria, the white blood cell count increases 4 to 5 times, from 20,000 to 300,000. However, it does not exceed 40,000. If it exceeds 40,000, leukemia is suspected.

The content (fraction) of the increased white blood cells also changes, and the number of neutrophils, which have the ability to fight, is almost 90% (it is usually 50-60%). This is a bit of a digression, but at that time, a phenomenon called “leftward migration” is observed. When blood cells are separated and fractionated by type, neutrophils are found on the left and lymphocytes and other blood cells are found on the right. When the number of neutrophils increases, it appears as if the peak of blood cell fractionation shifts to the left side.

In the leftward shift, neutrophils, including immature bacillary nucleated cells and retrospinal myelocytes, are seen. This is a phenomenon in which immature neutrophils (bacillary nuclei and myelocytes) are driven out due to the emergency situation of bacterial infection and all-out warfare. It is similar to the school children in the Pacific War or the Nazi Boy’s Army.

CRP, a marker of inflammation, rises dramatically in bacterial infections, usually above 10, and often over 30.

Viral infection

In viral infections, on the other hand, the white blood cell count does not increase much.

This is because the target and number are different. Bacterial infections literally attack bacteria. Bacteria can double in size in 20-30 minutes, so the body has to deal with a huge number of them. In order to fight against them, the human body also needs to increase the number of white blood cells to fight against them.

But in viral infections, the white blood cell count does not increase much. The reason is that the target is not the virus, but the cells infected by the virus. In fact, viruses cannot multiply by themselves, but only by entering and using the cells of other organisms. Also, the virus itself is too small to be killed by white blood cells one by one. So, instead, it targets cells that have been taken in by the virus and destroys the infected cells one by one. This is like killing a fellow zombie in a biohazard situation.

Cells take several hours to grow, even if they grow quickly. Therefore, cells infected with a virus do not grow that fast, so they do not need as many white blood cells to be eliminated. This is the reason why the white blood cell count does not increase much with viral infections. Also, the percentage of lymphocytes, which are good at defeating cells, increases because the target of attack is the infected cell. And LDH leaks out from the broken cells, which results in LDH⇧.

CRP does not increase that much with virulence, it is usually in the single digits. But if, for example, influenza is complicated by secondary bacterial pneumonia, the value jumps up.

Procalcitonin

Procalcitonin is a newer test than white blood cell count and CRP (not very new). Procalcitonin is characterized by the fact that it is elevated in bacterial but not viral cases. Therefore, it is acceptable to test it when differentiation is necessary.

Please note that due to insurance calculations, it is only covered once a month or so and is easily cut off for assessment.

Coronavirus

The result of blood sampling in coronavirus infection is not particularly different from other viruses.

In the same way, white blood cell count is mild ⇧ or almost flat, and LDH ⇧.

To begin with, coronavirus is a super major virus that causes so-called ‘cold’. Coronaviruses and rhinoviruses accounted for about 70-80%.

So this new type of corona is not particularly different from these in blood collection.

That’s all.Thank you again.