[jinjon (OP)]

Hallo,

I am wondering if there is an association between kidney function and kidney volume. I could imagine that decreased kidney volume could be associated with decreased kidney function because of the loss of nephrons.

But so far I  could not find a scientific article about this. Does anybody know more about his subject?

[evan_au]

There are people who are born with small kidneys, or have kidney size reduced due to corrective surgery (or one removed entirely due to transplantation into someone else). There are disease conditions (visible in ultrasound) which reduce the effective volume of kidneys. All of these conditions are likely to result in reduced kidney function.

To find if your kidneys are up to the task that you demand of them, your doctor will do a blood test, and perhaps a urine test. If these are found to be a problem, an ultrasound may be ordered.
- The instructions are likely to be the usual: "Drink plenty of water, exercise, and avoid excess alcohol and coffee..."

The blood test will look at Glomerular Filtration Rate and Creatine Clearance Rate.
https://en.wikipedia.org/wiki/Glomerular_filtration_rate

How well it works is more important than how big it is.

[evan_au]

In the context of COVID-19, cells lining capillaries, and kidney cells express the ACE2 receptor - that makes them targets for the SARS-COV2 virus (and subsequent counter-attack by antibodies and immune cells).

This has been found to cause tiny clots that float around your body, and get caught up in fine blood vessels (eg lungs, kidney & brain). So it would not be surprising to find reduced kidney function after a bout of COVID-19.

Vaccination may not prevent you getting infected (especially with Omicron), but it should reduce the severity of the disease, as your immune system will have a bit of a head-start.

See "RNA Expression Pattern" at https://en.wikipedia.org/wiki/Angiotensin-converting_enzyme_2