As we know that kidneys are the main sources for the removal of waste products from our body,
if kidney damaged than the whole system of body is disturbed.
Assalam-u-alaikum!
My name is Amina Sajjad. Today, I am going to discuss some biomarkers of kidneys. These
biomarkers are used for the diagnosis of acute kidney injury, chronic kidney diseases, kidney
failure, etc. These are mainly excreted out in the urine or detected in the blood. There are different
types of biomarkers some of which are described like creatinine, BUN, albumin, beta-2
microglobulin and cystatin-C.
Creatinine:
Creatinine is formed by the dehydration of creatine which is synthesized in liver, pancreas and
kidney from amino acids arginine, glycine and methionine. It is a waste product which is excreted
out in urine but due to kidney injury, it releases in the blood. The normal ranges for man is from
1.7-1.3 mg/dL and for woman is from 1.6 to 1.1 mg/dL.
BUN:
BUN is forms in the liver by the breakdown of proteins. Blood Urea Nitrogen is also a waste
product, if its level rises above the normal range it indicate kidney injury. Sometimes, some nonrenal factors can also raise the level of BUN. Thus, it is not considered as an ideal biomarker. The
normal reference rane is between 10 to 24 mg/dL.
Albumin:
Albumin is a protein found in the blood which helps to keep fluids from leaking out of the blood
vessels into other tissues. The albumin normal range is 3.5 to 5.0 mg/dL. If the albumin level in
the blood decreases or its level increases in the urine it indicates kidney damage.
Cystatin-C:
Cystatin-C is a recent biomarker which is used for the early diagnosis of kidney diseases and is
better than creatinine because it is less affected by non-renal factors. Cystatin-C is a low molecular
weight small protein that is produced in almost all the nucleated cells. The reference range of
serum Cystatin-C is 0.6 to 1.0 mg/L. If its level rises in blood it indicate kidney damage.
β2-microglobulin:
It is also a small protein that is present on the surface of the nucleated cells mostly in lymphocytes.
Its level should not be higher in the blood as well as urine. Higher levels of β2-microglobulin is
associated with not only kidney dysfunction but also with cardiovascular disorders and cancer.
The normal range in blood is 1.1 to 2.4 mg/L.
Risk Factors:
Some of the risk factors are high blood pressure, diabetes, heart disease, obesity, smoking, family
history of kidney diseases.
High blood pressure:
High blood pressure can cause arteries around the kidneys to narrow, weaken or harden. These
damaged arteries are not able to deliver enough blood to the kidney tissue. Damaged kidney
arteries don't filter blood well.
Diabetes:
Each kidney is made up of millions of tiny filters called nephrons. High levels of sugar in the
blood damage tiny blood vessels throughout the body including the filters of the kidneys. Many
people with diabetes also develop high blood pressure, which can damage kidneys too.
Heart Disease:
Having heart disease can directly affect your chances of developing kidney disease. And both have
the same risk factors like high blood pressure, diabetes. Changes in heart function may lead to
kidney damage by decreasing the blood supply to the kidneys. (Heart failure is a significant risk
factor for kidney disease. When the heart is no longer pumping efficiently it becomes congested
with blood, causing pressure to build up in the main vein connected to the kidneys and leading to
congestion of blood in the kidneys, too).
Obesity:
Being overweight can directly affect your kidneys. Extra weight forces the kidneys to work harder
and filter wastes above the normal level. Over time, this extra work increases the risk for kidney
dysfunctioning.
Smoking:
Smoking slows the blood flow to important organs like the kidneys and can make kidney disease
worse. Smoking also increases the risk of heart diseases and high blood pressure.
Family history of kidney diseases:
Some people may have a family history of kidney disease, where an inherited form of the disease
can run in families or passed down through one or more generations. These inherited conditions
are usually caused mutation in one of the genes.