Blood tests and other investigations become an integral part of CKD (Chronic Kidney Disease or Kidney Failure) patient’s life.

  1. Creatinine: This is the most important test which really matters. Basically, creatinine is a waste product of muscles which is removed from the body by kidneys.

The normal level of creatinine is up to 1.2mg/dl.

If your creatinine level is above 1.2mg/dl, then it means that your kidneys are not functioning properly.

  1. eGFR: The full form of eGFR is estimated Glomerular Filtration Rate. This is not a separate test. It is a number which is calculated from your creatinine level. The normal value is 90 or more than this.
  2. Creatinine Clearance Test: This test is more specific than normal creatinine test because this tells the amount of creatinine which is excreted by your kidneys. The normal value is 100ml/minute.

For example, if your creatinine clearance is 10ml/minute then it means that your kidneys are 90% failed. At this point the creatinine level in your blood is around 5.

  1. BUN: The full form of BUN is Blood Urea Nitrogen. This is a waste product of dietary protein which is excreted out of the body by kidneys. The normal value is 7 to 25 mg/dl. For measuring kidney function BUN is less reliable than creatinine test. This is because it depends upon your diet and the protein in the diet may be less or more.
  2. Urea: It is a waste product which is excreted by kidneys. Its normal value is 17 to 43 mg/dl. Less the kidneys work, more the urea will increase in blood.
  3. Sodium: Its normal value is 136 to 146 mEq/l. If you have more sodium in your blood, then you will have water retention which will increase your BP and damage your heart and kidneys. So, a CKD patient should take salt restricted diet.
  4. Potassium: The normal range of potassium is 3.5 to 5.1 mEq/l. Excess of potassium in blood leads to problems of nerves, muscles, and heart. Patient experiences palpitations and nervousness.
  5. Calcium & Phosphorus: For strong bones Calcium and phosphorus are very important. When calcium increases in the blood, phosphorus starts to decrease. The normal range of calcium is 8.8 to 10.3 mg/dl. The normal range of phosphorus is 2.3 to 3.7 mg/dl.
  6. PTH: The full form of PTH is parathyroid hormone. It maintains the balance of calcium and phosphorus in the blood.    
  7. Bicarbonate: It is a form of carbon dioxide, and it measures the acidity of blood. Kidneys regulate the bicarbonate levels. CKD reduces the level of bicarbonate in the blood which leads to metabolic acidosis. This leads to more worsening of CKD. A nephrologist prescribes baking soda to neutralize acidity in the blood.
  8. Albumin: The normal range of albumin is 3.2 to 4.6 gm/dl. This is a protein. When the kidneys fail, the albumin starts leaking in the urine, which reduces the albumin level in blood.
  9. Hemoglobin: It is very important to measure hemoglobin because it carries oxygen in the blood and without oxygen we cannot survive.

As kidneys fail, the patient’s hemoglobin level starts to fall, and the patient becomes anemic. 

Anemia causes tiredness and breathlessness. The normal range of hemoglobin is 11.5 to 15 gm/dl.

  1. Iron (Ferritin): It is very important to have normal level of iron in the blood otherwise hemoglobin becomes low. The normal value of iron is 50 to 175 µgm/dl. If your iron level is low, then you will be given iron supplements.
  2. Urine Routine & Microscopic: This is a very simple and affordable test but very important for CKD. There should be no proteins, glucose, leukocyte esterase, blood, RBCs in urine. Pus cells should be in the range 0 to 5 /hpf. The presence of protein in urine is an early sign that kidneys may fail in future.
  3. HbA1c, Lipid profile, LFT: A CKD patient should get these tests done every 3 months. These tests tell us about the condition of diabetes, heart and liver.
  4. USG KUB: The USG tells us about the size of the kidneys, parenchymal echotexture, corticomedullary differentiation, hydronephrosis, cysts. This test helps to diagnose CKD and polycystic kidney disease.
  5. Kidney biopsy: In this a small portion of kidney tissue is taken out by a syringe and then examined under the microscope. Sometimes kidney biopsy is the only way left to know about problem in your kidneys especially in cases of autoimmune disorders.