Labrotory tests for kidney

Labrotory tests for kidney:

Labrotory tests for kidney

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Routine urine examination

Physical Examination of Urine:

Physical Examination of Urine Introduction Routine urine examination is detailed analysis of urine. It helps detect alterations in the composition of the urine which help in the diagnosis of many disorders. When a sample of urine is submitted to a pathological laboratory, the following examinations are done:

Physical Examination:

Physical Examination Volume Color Appearance Reaction Odor Sediment formation at the bottom of a container after collection Specific Gravity

Volume:

Volume Normal volume of an early morning mid–stream sample is 50 – 300ml. If it is more than 500ml, it indicates diabetes or polyuria (frequent passing of urine). If it is less than 20ml, it indicates some kidney disorder.

Physical Examination:

Physical Examination Volume Color Appearance Reaction Odor Sediment formation at the bottom of a container after collection Specific Gravity

Color :

Color The normal color of urine is pale yellow. If it is dark yellow to orange, it indicates some liver disorder. If it is white, it shows the presence of pus. If it is pink to red, it indicates the presence of red blood cells. If it is brownish black, it indicates the presence of melanin or homogenistic acid (a rare disorder). If it is blue to green, it is a liver disorder. Sometimes, due to the intake of some food or medicines also, one could notice a change in the color or their urine e.g. the intake of beet imparts a reddish color to urine. The intake of vitamin B capsules gives a dark yellow color to it, if rimfamycin is taken, it gives an orange tinge to the urine.

Physical Examination:

Physical Examination Volume Color Appearance Reaction Odor Sediment formation at the bottom of a container after collection Specific Gravity

Appearance :

Appearance Usually, it is clear, sometimes, it is cloudy. Sometimes, it is turbid due to the presence of WBCs (White Blood Cells), epithelial cells. Sometimes, it is hazy due to mucus. Smoky, due to red blood cells. Milky due to chyle (lymph).

Physical Examination:

Physical Examination Volume Color Appearance Reaction Odor Sediment formation at the bottom of a container after collection Specific Gravity

Reaction:

Reaction Usually acidic pH range 4.5 – 7.5. If pH less than 4.7 it is more acidic. If pH more than 7.5 it is more alkaline.

Physical Examination:

Physical Examination Volume Color Appearance Reaction Odor Sediment formation at the bottom of a container after collection Specific Gravity

Odor:

Odor Usually, it is aromatic in normal conditions. It has a fruity odor in diabetes. Ammoniacal odor in cases of urine retention. Foul smelling due to urinary tract infection.

Physical Examination:

Physical Examination Volume Color Appearance Reaction Odor Sediment formation at the bottom of a container after collection Specific Gravity

Sediment formation at the bottom of a container after collection:

Sediment formation at the bottom of a container after collection Usually, there is no or very little formation of sediment in normal conditions. If pus cells, red blood cells, cysts or epithelial cells are present, the sedimentation rate ranges from moderate to high.

Physical Examination:

Physical Examination Volume Color Appearance Reaction Odor Sediment formation at the bottom of a container after collection Specific Gravity

Specific Gravity:

Specific Gravity Usually varies from 1.003 to 1.060. A low special gravity indicates diabetes insipidus or kidney infection (chronic). High specific gravity indicates diabetes mellitus or acute kidney infection.

Chemical Examination of Urine:

Chemical Examination of Urine Protein Urine Glucose Urine Ketone Urine Bilirubin Blood Additional Chemical Tests

Chemical Examination of Urine:

Chemical Examination of Urine Protein Urine Glucose Urine Ketone Urine Bilirubin Blood Additional Chemical Tests

Protein:

Protein Normally absent. Present in kidney disorders, dehydration, heart disease, and severe diarrhea. Sometimes, due to an excessive muscular exercise, prolonged cold baths, excessive protein intake or vaginal discharge in the urine, the test shows the presence of protein.

Chemical Examination of Urine:

Chemical Examination of Urine Protein Urine Glucose Urine Ketone Urine Bilirubin Blood Additional Chemical Tests

Urine Glucose :

Urine Glucose Renal Causes of glucose in the urine Signs suggestive of Renal Tubular disease Serum Glucose <180 mg/dl Glucose Tolerance Tests are normal Ketosis absent Specific Causes Fanconi's Syndrome Toxic renal tubular disease Lead Toxicity Mercury Toxicity Degraded Tetracycline Inflammatory renal disease Acute Glomerulonephritis Nephrosis Increased GFR without tubular damage

Urine Glucose :

Urine Glucose Causes of false positive glucose on Urinalysis Ascorbic acid Nalidixic Acid Cephalosporins Probenacid Ketones Levodopa Causes of false negative glucose on Urinalysis Increased specific gravity Uric Acid Vitamin C

Chemical Examination of Urine:

Chemical Examination of Urine Protein Urine Glucose Urine Ketone Urine Bilirubin Blood Additional Chemical Tests

Urine Ketone:

Urine Ketone Normal Negative Positive Dehydration Starvation or Low Carbohydrate Diets Diabetic Ketoacidosis (DKA) Alcoholic ketoacidosis Isopropanol toxicity Pregnancy Causes of false positive ketones on Urinalysis Low Urine pH (acidic) Increased Urine Specific Gravity Phenolphthalein Levodopa Causes of false negative ketones on Urinalysis Delayed urine exam

Chemical Examination of Urine:

Chemical Examination of Urine Protein Urine Glucose Urine Ketone Urine Bilirubin Blood Additional Chemical Tests

Urine Bilirubin :

Urine Bilirubin Normal Negative for Bilirubin Positive for Conjugated Bilirubin Hepatitis Viral Hepatitis Toxic Hepatitis Drug Induced Hepatitis Biliary tract obstruction Positive for Urobilinogen Hepatitis Liver disease Cirrhosis Liver Metastases Liver infarction Hemolytic Jaundice

Chemical Examination of Urine:

Chemical Examination of Urine Protein Urine Glucose Urine Ketone Urine Bilirubin Blood Additional Chemical Tests

Blood:

Blood Normally absent. Present in acute kidney infections, kidney cancer, tuberculosis of the kidneys, chronic infections, stone formation in the kidneys, severe burns or a reaction to blood transfusion.

Chemical Examination of Urine:

Chemical Examination of Urine Protein Urine Glucose Urine Ketone Urine Bilirubin Blood Additional Chemical Tests

Additional Chemical Tests:

Additional Chemical Tests Non–glucose Sugars Lactose: May be present normally. It is present in lactating women. Fructose: Present in liver disorders. Pentoses : Are present due to drug therapy or hereditary conditions.

Non–glucose reducing substances:

Non–glucose reducing substances Ascorbic acid: Present in Vitamin C therapy. Salicylic acid: Due to drugs having salicilates . Menthol: Due to the intake of food containing menthol.

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Nitrite Present due to bacterial infection Indican It is present in very low concentrations. It is increased due to intestinal obstruction, cholera, typhoid fever or peritonitis. Sometimes, it is due to the intake of diets rich in proteins.

Microscopic Examination of Urine:

Microscopic Examination of Urine Pus Cells Epithelial cells Casts Amorphous Material Crystals Bacteria Yeast cells Parasites

Microscopic Examination of Urine:

Microscopic Examination of Urine Pus Cells Epithelial cells Casts Amorphous Material Crystals Bacteria Yeast cells Parasites

Pus Cells:

Pus Cells Normally 2 to 3 pus cells are present in HPF (high power field of microscope). If more than 5 it indicates urinary tract infection or non infectious condition such as fever, stress, dehydration irritation to urethra, bladder or urethra.

Microscopic Examination of Urine:

Microscopic Examination of Urine Pus Cells Epithelial cells Casts Amorphous Material Crystals Bacteria Yeast cells Parasites

Epithelial cells:

Epithelial cells Normally two to three present in males. Normally two to five present in females. More than five epithelial cells per HPF indicates tubular damage, pyelonephritis or kidney transplant rejection.

Microscopic Examination of Urine:

Microscopic Examination of Urine Pus Cells Epithelial cells Casts Amorphous Material Crystals Bacteria Yeast cells Parasites

Casts:

Casts Normally absent. There are hyaline cysts, red cell cysts, white cell cysts, granular cysts, waxy cysts, and fatty cysts. They are present due to kidney disorders. Occasional Hyaline cysts may be present due to physical exercise and physiological dehydration. Granular cysts may be present after strenuous exercise for a short duration.

Microscopic Examination of Urine:

Microscopic Examination of Urine Pus Cells Epithelial cells Casts Amorphous Material Crystals Bacteria Yeast cells Parasites

Amorphous Material:

Amorphous Material Amorphous urates of sodium, potassium or calcium are present normally. Amorphous phosphates of calcium and magnesium are present normally.

Microscopic Examination of Urine:

Microscopic Examination of Urine Pus Cells Epithelial cells Casts Amorphous Material Crystals Bacteria Yeast cells Parasites

Crystals:

Crystals Uric acid, calcium sulphate , calcium oxalate and ammonium magnesium phosphate (triple phosphate) crystals are indicative of the presence of kidney stones. Hippuric acid, calcium carbonate, ammonium biurate and calcium phosphate crystals are non–significant. Following crystals, found in acidic urine indicate abnormal metabolism – cystine , cholesterol, leucine , tyrosine, bilirubin , hematoidin and sulphonamides .

Microscopic Examination of Urine:

Microscopic Examination of Urine Pus Cells Epithelial cells Casts Amorphous Material Crystals Bacteria Yeast cells Parasites

Bacteria:

Bacteria Normally absent. If present indicates infection.

Microscopic Examination of Urine:

Microscopic Examination of Urine Pus Cells Epithelial cells Casts Amorphous Material Crystals Bacteria Yeast cells Parasites

Yeast cells:

Yeast cells Normally absent. May be present in acidic urine containing sugar.

Microscopic Examination of Urine:

Microscopic Examination of Urine Pus Cells Epithelial cells Casts Amorphous Material Crystals Bacteria Yeast cells Parasites

Parasites:

Parasites Normally absent. If present, they are Trichomonas Vaginalis (from vagina) or Trichononas Hominis (from rectum).

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24 Hour Urine Protein Urine Protein to Creatinine Ratio Serum Creatinine Blood Urea Nitrogen (BUN) Creatinine Clearance Uric Acid

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24 Hour Urine Protein Urine Protein to Creatinine Ratio Serum Creatinine Blood Urea Nitrogen (BUN) Creatinine Clearance Uric Acid

24 Hour Urine Protein :

24 Hour Urine Protein Interpretation of 24 hour Urine Protein Confirm Sample adequacy Calculate expected 24 hour Urine Creatinine excretion Inadequate sample suggested if discrepancy Findings Normal Proteinuria < 4 mg/m2/hour (<150 mg/day) Abnormal Proteinuria 4-40 mg/m2/hour Nephrotic Syndrome Proteinuria > 40 mg/m2/hour

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24 Hour Urine Protein Urine Protein to Creatinine Ratio Serum Creatinine Blood Urea Nitrogen (BUN) Creatinine Clearance Uric Acid

Urine Protein to Creatinine Ratio :

Urine Protein to Creatinine Ratio Indication Monitor persistant Proteinuria Efficacy More accurate than 24 Hour Urine Protein collection Most accurate if first morning void is used Technique: Random urine collection Urine Creatinine in mg Urine Protein in mg Calculate Urine Protein mg to Urine Creatinine mg Ratio

Urine Protein to Creatinine Ratio :

Urine Protein to Creatinine Ratio Interpretation of Urine Protein to Urine Creatinine Ratio Child under age 2 years Normal Ratio <0.5 Adults and children over age 2 years Normal ratio <0.2 grams protein per gram Creatinine Correlates with 0.2 g protein/day Nephrotic Ratio >3.5 (correlates with 3.5 g protein) Interpretation of Urine Albumin to Creatinine Ratio Normal Ratio (in general <30 mg/g is normal) Men: < 0.017 (or 17 mg albumin to 1 gram Creatinine ) Women: <0.025 (or 25 mg albumin to 1 gram Creatinine ) Microalbuminuria : 30-300 mg albumin/g Creatinine Macroalbuminuria : >300 mg albumin/g Creatinine

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24 Hour Urine Protein Urine Protein to Creatinine Ratio Serum Creatinine Blood Urea Nitrogen (BUN) Creatinine Clearance Uric Acid

Serum Creatinine :

Serum Creatinine Measuring serum creatinine is a useful and inexpensive method of evaluating renal dysfunction. Creatinine is a non-protein waste product of creatine phosphate metabolism by skeletal muscle tissue. Creatinine production is continuous and is proportional to muscle mass.

Serum Creatinine :

Serum Creatinine Creatinine is freely filtered and therefore the serum creatinine level depends on the Glomerular Filtration Rate (GFR). Renal dysfunction diminishes the ability to filter creatinine and the serum creatinine rises. If the serum creatinine level doubles, the GFR is considered to have been halved. A threefold increase is considered to reflect a 75% loss of kidney function.

Serum Creatinine :

Serum Creatinine Reference values for serum creatinine : Adult males : 0.8 - 1.4 mg/dl: values are slightly higher in males due to larger muscle mass Adult females: 0.6 - 1.1 mg/dl: creatinine clearance is increased in pregnancy, resulting in lower serum levels Children: 0.2 - 1.0 mg/dl: slight increases with age because values are proportional to body mass A panic value for creatinine is 10 mg/dl in nondialysis patients.

Serum Creatinine :

Serum Creatinine Increased serum creatinine levels are seen in: Impaired renal function Chronic nephritis Urinary tract obstruction Muscle diseases such as gigantism, acromegaly , and myasthenia gravis Congestive heart failure Shock

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The only important pathological condition that causes a significant increase in the serum creatinine level is damage to a large number of nephrons . Unlike the BUN, the serum creatinine level is not affected by hepatic protein metabolism. Tests to measure serum creatinine , urine creatinine , and creatinine clearance are all used only to evaluate renal function. Only renal dysfunction changes the results. The serum creatinine level does not rise until at least half of the kidney's nephrons are destroyed or damaged. Because creatinine levels rise and fall more slowly than BUN levels, creatinine levels are often preferred to monitor renal function on a long-term basis.

Serum Creatinine :

Serum Creatinine D ecreased creatinine levels may be seen in: the elderly, persons with small stature, decreased muscle mass, or inadequate dietary protein. Muscle atrophy can also result in decreased serum creatinine level. If muscle atrophy is suspected, assessment of serum creatine , an important enzyme necessary for normal muscle function, is done.

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24 Hour Urine Protein Urine Protein to Creatinine Ratio Serum Creatinine Blood Urea Nitrogen (BUN) Creatinine Clearance Uric Acid

Blood Urea Nitrogen (BUN) :

Blood Urea Nitrogen (BUN) Blood urea nitrogen (BUN) measures the amount of urea nitrogen, a waste product of protein metabolism, in the blood. Urea is formed by the liver and carried by the blood to the kidneys for excretion. Because urea is cleared from the bloodstream by the kidneys, a test measuring how much urea nitrogen remains in the blood can be used as a test of renal function. However, there are many factors besides renal disease that can cause BUN alterations, including protein breakdown, hydration status, and liver failure.

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Adult : 7-20 mg/100 ml; men may have slightly higher values than women Pregnancy : values decrease about 25% Newborn : values slightly lower than adult ranges Elderly : values may be slightly increased due to lack of renal concentration

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Increased BUN An increase in the BUN level is known as azotemia . An elevated BUN may be caused by: Impaired renal function Congestive heart failure as a result of poor renal perfusion Dehydration Shock Hemorrhage into the gastrointestinal tract Acute myocardial infarction Stress Excessive protein intake or protein catabolism

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Diseased or damaged kidneys cause an elevated BUN because the kidneys are less able to clear urea from the bloodstream. In conditions in which renal perfusion is decreased, such as hypovolemic shock or congestive heart failure, BUN levels rise. A patient who is severely dehydrated may also have a high BUN due to the lack of fluid volume to excrete waste products. Because urea is an end product of protein metabolism, a diet high in protein, such as high-protein tube feeding, may also cause the BUN to increase. Extensive bleeding into the gastrointestinal (GI) tract will also cause an elevated BUN because digested blood is a source of urea. For example, a hemorrhage of one liter of blood into the GI tract may elevate the BUN up to 40mg/ml.

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Decreased BUN A decreased BUN may be seen in: Liver failure Malnutrition Anabolic steroid use Overhydration , Which can result from prolonged intravenous fluids Pregnancy (due to increased plasma volume) Impaired nutrient absorption Syndrome of inappropriate anti-diuretic secretion (SIADH)

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Because urea is synthesized by the liver, severe liver failure causes a reduction of urea in the blood. Just as dehydration may cause an elevated BUN, overhydration causes a decreased BUN. When a person has "syndrome of inappropriate anti-diuretic secretion" (SIADH), the anti-diuretic hormone responsible for stimulating the kidney to conserve water causes excess water to be retained in the bloodstream rather than being excreted into the urine. SIADH can cause the BUN level, along with other important substances, to decrease because the fluid volume of the bloodstream may significantly increase.

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24 Hour Urine Protein Urine Protein to Creatinine Ratio Serum Creatinine Blood Urea Nitrogen (BUN) Creatinine Clearance Uric Acid

Creatinine Clearance :

Creatinine Clearance A creatinine clearance test measures the rate at which the kidneys clear creatinine from the blood. Creatinine is a substance that is easily excreted by the kidney in healthy people. Because all the creatinine filtered by the kidneys in a given time interval is excreted into the urine, creatinine levels are equivalent to the glomerular filtration rate (GFR); the rate at which the kidneys process blood through the glomerular system. A creatinine clearance test compares the serum creatinine with the amount of creatinine excreted in a volume of urine for a specified time. A 24-hour time frame is most common. At the beginning of the test, the patient empties his bladder and the urine is discarded. Then, all urine voided during the specific time period is collected. Sometime during the test period a blood sample is drawn to determine the serum creatinine , so that the amount excreted in the urine and the amount remaining in the blood can be compared. The nurse has an important role in instructing the patient about the purpose of the test and the procedures that will be used.

Creatinine Clearance :

Creatinine Clearance Expected creatinine clearance values (expressed as number of milliliters per minute per 1.72 meters squared of body surface) Adult males : 97 - 137 ml/min Adult females : 88 - 128 ml/min Pregnancy : may be as high as 150 - 200 ml/min Elderly : values diminish with age even if no renal disease exists, as the GRF declines about 10% per decade after age 50

Creatinine Clearance :

Creatinine Clearance Decreased creatinine clearance A decrease in the kidney's ability to clear creatinine is an indication of decreased glomerular function. The creatinine clearance test is used to diagnose renal dysfunction and is also used to evaluate the progression of renal disease. A minimum creatinine clearance of 10ml/min is necessary to maintain life without the use of renal or peritoneal dialysis.

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24 Hour Urine Protein Urine Protein to Creatinine Ratio Serum Creatinine Blood Urea Nitrogen (BUN) Creatinine Clearance Uric Acid

Uric Acid :

Uric Acid Uric acid is the end product of purine metabolism. Purines are obtained from both dietary sources and from the breakdown of body proteins. Organ meats such as liver, kidneys, and sweetbreads, sardines, anchovies, lentils, mushrooms, spinach, and asparagus are all rich sources of purines . The kidneys excrete uric acid as a waste product. The kidneys excrete two-thirds of the uric acid produced daily; the remaining one-third is excreted in the stool. The exact level of uric acid that is considered pathological is controversial. In recent years, it has been recognized that the normal ranges of uric acid are quite wide. Because of this wide range, and because uric acid levels show day-to-day and seasonal variations in the same person, several uric acids levels may be ordered over a period of time. Urine uric acid levels may also be used to evaluate gout or determine oversecretion of uric acid.

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Reference values: Serum Uric Acid Adult males : 2.0 - 7.5 mg/dl Adult females : 2.0 - 6.5 mg/dl; in early pregnancy uric acid levels fall by about one-third but rise to non-pregnant levels by term Children (ages 10-18) Males: 3.6 - 5.5 mg/dl; significant rise in males at ages 12-14 coincides with puberty. Females: 3.6 - 4 mg/dl Elderly: Males older than 40: 2 - 8.5 mg/dl Females older than 40: 2 - 8.0 mg/dl; rise in women related to menopause The normal range for urinary uric acid is between 250 - 750 mg over a 24-hour period. Uric acid levels tend to vary day to day. It is also important to check the laboratory reference values for each work setting.

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An elevated blood uric acid level , also known as hyperuricemia , is seen in: Gout Renal disease and renal failure Alcoholism Dehydration Leukemia and lymphoma Starvation Metabolic acidosis Toxemia of pregnancy Infectious mononucleosis Hyperlipidemia Hemolytic anemia Excessive cell destruction associated with chemotherapy and radiation treatment

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DIPT. OF MEDICINE SOURAV BAUR BASAVESHWARA MEDICAL COLLEGE ,CHITRADURGA THANK YOU