The Dialysis Patient and His Monthly Laboratory Tests

     

As a new patient before, I was not familiar with the significance of the results of my monthly laboratory tests. Our Nephrologist read my result and if she tells me that a certain value on my test is high or low, I just obey what she tells me to avoid and not to do and buy the medicines that are in the prescription. Now that I have been undergoing dialysis for almost eight years, I know the importance of the correct interpretation of my laboratory results. We have many laboratory tests every second week of the month. Before we are hooked on the dialysis machine, the nurses take a specific amount of our blood which they then put in two test tubes to be sent to the Outpatient Laboratory for the following tests: Complete Blood Count (CBC), Pre-dialysis: Creatinine, Blood Urea Nitrogen (BUN), Inorganic Phosphorus, Calcium, Potassium, Albumin, Sodium, and Blood Uric Acid (BUA). Post -dialysis: Creatinine and BUN.

        Why the so many tests. Now I know that CBC is done to monitor the value of Hemoglobin, Red Blood Cell (RBC), White Blood Cell (WBC) and other components of my blood. Hemoglobin value of a dialysis patient usually does not reach the normal value of a normal person which is 12 - 14. If the patient reaches a value of more than 12, the doctor will advise him to inject Erythropoietin for once a week. Injection of the synthetic hormone is stopped if the value is 13 or more. This is done to prevent too much viscosity or thickness of the blood of the patient that might result to stroke or heart attack. If the value is below 11, this means that production of RBCs is very low and the injection should be done twice or thrice a week depending on how low is the Hemoglobin. Hemoglobin combined with Iron help in the distribution of Oxygen in the tissues of the body through the Red Blood Cells. Erythropoietin is a hormone that helps in the production of RBC and is normally secreted or produced by the kidneys of a normal person. If the kidneys are damaged, the production of Erythropoietin stops. That is why synthetic Erythropoietin injection was developed to replace the natural Erythropoietin of a dialysis patient. It took many years of study and research to develop this synthetic hormone which is derived from cloning the gene for Erythropoietin. Low level of Hemoglobin and RBC results to muscle weakness and fatigue and will strain the heart while the patient is on dialysis. A blood transfusion is necessary to bring the Hemoglobin count to at least 9 or 10 up to 11 which is better. Anemic patients who practice too much physical exertion or rigorous exercises are exposing their heart to too much stress making the heart to compensate resulting to Cardio-Megally or enlargement of the heart.

       I know now that a high value of White Blood Cell (WBC) indicates an infection somewhere in my body that needs to be detected in order for the doctors to determine what type of anti-biotic they will prescribe me. A low WBC count indicates a viral infection or other diseases like Leukemia or cancer. It can also be caused by Rheumatoid Arthritis and other auto-immune diseases.

        Low and high Platelet count indicate an infection or disease. High platelet count could result to stroke or heart attack and low platelet count results in skin bruising and bleeding since it is the Platelet that is responsible in blood clotting.

      I know now that monitoring my blood Phosphorus level is important because high level of Phosphorus leads to increased mortality in dialysis patients because Phosphorus binds with Calcium in the blood to form Calcium Phosphate crystals which accumulate in the organ tissues including the heart, muscles and joints resulting to cardio-vascular disease and painful inflammation especially when the patient has undergone many years of dialysis. These crystals are mostly deposited in the lower limbs causing the skin to itch that the patient cannot avoid scratching his skin which result to small lacerations that expose it to bacteria that cause infection called Cellulitis which make the patient prone to Sepsis (blood infection) if left untreated with anti-biotic. Sepsis is a serious condition which leads to morbidity and death. Taking too much anti-biotics is bad for the liver. When the liver is damage, death of the dialysis patient will surely come next. Low level of Phosphorus among dialysis patients is very rare because Phosphorus in foods eaten by the patients accumulate in the blood since it is the kidney that excretes excess Phosphorus. Dialysis patients have damaged kidneys and excess Phosphorus has no way to get out of the body. Thus, it binds with Calcium and gets deposited in muscles, tissues and joints of the patient. Small amount of Phosphorus is removed by dialysis but most of the Phosphorus is in the tissues of the dialysis patient and hard to remove. Hyper-Phosphatemia or excess Serum Phosphate is treated with phosphate binders. To prevent additional phosphorus from entering the blood stream phosphate binders are taken by the patient after each meal. Effective phosphate binders are: Calcium Carbonate and Sevelamer Carbonate. Calcium binds with Phosphorus during digestion of foods in the intestine and is excreted or removed together with other bodily waste. Sevelamer acts like a sponge that absorbs Phosphorus and is also removed together with other bodily waste. The dialysis patient should still avoid eating foods high in Phosphorus since the phosphate binders cannot bind all the Phosphorus that he have eaten.

           As mentioned above, excess Phosphorus binds with Calcium. In this way, the level of Calcium in the blood is also monitored because high amount of Calcium causes Calcification and is detrimental to the: tissues of the organs and muscles and joints. Low level of Calcium however, results to Hypo-Calcemia which causes the bone to become weak and brittle. That is why Calcium Carbonate is prescribed to patients with low level of Calcium.

       Monitoring the Potassium level in the blood is also necessary because very high level of 7 and above can cause the heart beat to stop that will kill the patient. Death Row prisoners about to be executed are given overdose of Potassium that will cause painless death. Injured and sick animals are put to death by high dose of potassium. Low level of Potassium (Hypo-Kalemia) causes muscle weakness and fatigue, muscle cramps and twitching and irregular heartbeat. Just like Phosphorus, Potassium is accumulated in the blood of dialysis patients because of their impaired kidneys. Excess Potassium is removed by regular dialysis but some patients eat foods that are high in Potassium two or more days before dialysis. That is why Potassium builds up to dangerous level in the blood before they are dialyzed.

        Level of Albumin in the blood is monitored regularly since the dialysis patient is on low protein diet which makes the Albumin level to fall down. Serum Albumin is responsible for maintaining the volume of the blood. Low level of Serum Albumin results to less blood volume and the excess water in the blood is deposited in the muscles and body cavities including the cavity around the heart. This makes the heart exert more effort resulting to stress and eventual heart damage if not remedied. Low level of Albumin also results to leaking body nutrients out of the blood vessels depriving the muscles and organs of vitamins and minerals. This also results to Edema or swelling of the legs and Ascite (accumulation of water in the cavity of the stomach or abdomen which can lead to shortness of breath and peritoneal cavity infection). Some patients eat salty foods and as a result they feel very thirsty and drink a lot of water. Excess water is then stored in the cavity of the abdomen; more so if their Albumin count is low due to kidney and other disease like that of the liver. Low level of Albumin is corrected by ingestion of the dialysis patient of two to three egg whites per day. Egg yolk contains high amount of Phosphorus and Cholesterol and should be avoided.

       The amount of serum sodium is also monitored regularly. High value of sodium (above 145) can cause high blood pressure and Edema which could lead to stroke and heart attack. Excess water in the body of a dialysis patient is also harder to remove during dialysis if the sodium concentration in the blood is high. This strains the heart and creates a feeling of discomfort during dialysis. The patient is advised to lessen sodium intake and drink small amount of water in order to stabilize the sodium level and the excess water removed by regular dialysis of two to three times per week. Three times per week is the recommended dialysis session but dialysis patients limit it to one to two times per week due to financial constraints. Low level of Serum Sodium (below 135) is also bad for the dialysis patient because this could lead to hypo-tension (low blood pressure) and painful cramps during dialysis. Very low blood pressure could result to dizziness, shortness of breath, restlessness, seizures and coma.

        I know now that monitoring the Blood Uric Acid (BUA) is also important since this indicates whether the patient is prone to painful inflammations like Gout and Arthritis. Purine (the derivative of Uric Acid) is present in most fruits like oranges and berries. Foods high in Uric Acid are beans, meat and internal organs. Uric Acid is a crystalline substance which is the product of Nitrogenous Metabolism (digestion) and if it accumulates in high quantity in the blood of the dialysis patient could lead to painful swollen joints. Excess Uric Acid is removed by the normal kidney but dialysis patients have damaged kidneys, that is why Uric Acid accumulates in the blood. Some Uric Acid is removed by dialysis but some patients eat foods with high amount of Uric Acid two to three days before dialysis and that is why excess Uric Acid is accumulated before they are dialyzed. Excess Uric Acid is also treated with Allo-Purinol.

          Before a patient is diagnosed by the doctor of having kidney disease, his blood sample is taken for CBC, Creatinine and Blood Urea Nitrogen (BUN) tests. The laboratory tests would indicate if he is Anemic, with high value of Creatinine and BUN which clearly indicate kidney damage. Creatinine test indicate if the kidneys are functioning normally or are partially or totally damaged. A value of Creatinine of 2 to 3 means the patient has Chronic Kidney Failure and dialysis is not yet prescribed by the doctor. Creatinine value of 4-5 means there is substantial damage to the kidneys and dialysis of once a week is advised by the doctor. Values of more than 6-10 indicates major Chronic Kidney Disease (CKD) and values of more than 11 indicate End Stage Kidney Disease (ESKD) and two to three times dialysis sessions per week is needed. High BUN indicates that the blood is high in nitrogenous wastes that are accumulated because of kidney damage. Normal kidneys filter out these wastes. A clear example of this is when a normal person eats large amount of protein or meat, the by-product of protein digestion or metabolism is Urea and other nitrogenous wastes and is efficiently remove regularly 24/7 by the normal kidneys. It is noted that the urine of that normal person has a strong pungent smell like Ammonia. If the kidneys are impaired, these nitrogenous wastes including Urea is accumulated in the blood of the dialysis patient and can only be removed by dialysis. Large amount of Urea and other nitrogenous wastes in the blood results to the condition of Uremia (the blood becomes acidic and toxic). Serious Uremia affects the brain function of patients resulting to anxiety, restlessness and confusion. If left untreated, uremic patients suffers brain damage and eventually die.

       Levels of Serum Creatinine and BUN are monitored regularly by the doctor to find out if the degree of damage to the kidneys is improving or has worsened. Pre-dialysis (before dialysis) and Post-dialysis (after dialysis) value of Creatinine and BUN is taken so the doctor will see if the dialysis patient is dialyzed sufficiently or efficiently. High value of BUN and Creatinine even after dialysis indicates insufficient dialysis due to the type of dialyzer, length of time and frequency of dialysis and the Blood Flow Rate (BFR) of the dialysis machine. Faster BFR means more volume of blood passing the dialyzer is cleaned. This is limited though due to the condition of the patient if he has a serious heart problem or his blood pressure is too high or too low. Dialysis patients with minor heart problem can tolerate up to 300 ml per minute BFR. The type of the dialyzer also affects the efficiency of dialysis. High Flux Dialyzer (HFD) cleans more efficiently compared to the Low Flux Dialyzer. High Flux Dialyzer is not tolerated at high BFR by some patients with heart condition. If dialysis is insufficient and not efficient, it means that more toxins are retained in the blood that could increase the risk of morbidity and mortality among dialysis patients.

          The above tests are only the monthly laboratory tests of dialysis patients. Other laboratory tests are done depending on the condition and symptoms experienced by the patient to confirm if complications from dialysis is present. It is very important to fully understand the interpretation and meaning(s) of the results of these tests to guide the patient in dealing with his disease. This also will give the patient a positive outlook in life for him to be disciplined to resist temptations from: eating excess foods that could aggravate his condition, give him courage and hope to face challenges, pain and uncertainties that will come his way.