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  2. 2. INTRODUCTION • Urinalysis is a test done to examine the physical, chemical and microscopic content of the urine. In this context, we’ll relate it to urine R/E. • Examination of urine is the oldest among tests in the history medical laboratory and it is used as an aid in diagnosis and monitoring of a number of disorders or conditions that are: a) Haematological b) Metabolic c) Hepatic and renal d) Urological
  3. 3. RENAL ANATOMY AND PHYSIOLOGY • The renal system is made up of two kidneys, two ureters, one bladder and one urethra. • The kidneys are two bean shaped organs located under the lowermost part of the of the ribs in the posterior abdominal cavity. • Nephron is the function unit of the kidneys and each kidneys contains appx one million nephrons. Each nephron consists of a glomerulus, essentially, the filtering system. • The kidney is a highly discriminating organ, which maintains the internal environment by selectively excreting or retaining various substance according to the specific body needs. • Approximately 1,200 millilitres of blood flow through the kidneys each minute.
  4. 4. RENAL ANATOMY AND PHYSIOLOGY The kidneys perform the following functions:  Regulation of water and electrolyte (chloride, potassium, calcium, hydrogen etc) balance as well as the regulation of acid-base balance of the blood.  Regulation of body fluid osmolality and electrolytes  Excretion of metabolic waste products and foreign chemical. The kidneys are the primary means of eliminating metabolic waste products from the body. These include urea from metabolism of amino acids, bilirubin from haemoglobin breakdown, uric acid from nucleic acids and creatinine from muscle creatine).
  5. 5. RENAL ANATOMY AND PHYSIOLOGY Secretion of hormones such as renin. Gluconeogenesis, thus, synthesis of glucose of from amino acids and other precursors including lactate and glycerol during prolonged fasting.
  7. 7. THE COMPOSITION OF URINE • NORMAL URINE CONSTITUENTS Water (about 95% of urine) Urea Creatinine Uric acid Electrolytes
  8. 8. THE COMPOSITION OF URINE • ABNORMAL URINE CONSTITUENTS Glucose Protein Bile pigments Blood cells Cast, parasites and bacterial microbes
  9. 9. FACTORS AFFECTING THE COMPOSITION OF URINE •Diet and nutritional status •Condition of body metabolism •Ability of kidney function •Level of contamination with pathogenic microorganisms or non- pathogenic microflora
  10. 10. RENAL THRESHOLD •This is the highest concentration of a substance, which is present in the blood before it is found in the urine. •Glucose has a high threshold, because it is completely absorbed from the glomerular filtrate and only found in urine when blood glucose level is markedly raised.
  11. 11. The quality of a sample is as good as the results. For reliable urinalysis, the urine must be properly collected. • A freshly voided urine specimen is adequate for most urinalysis. Generally, about 10mls of urine is required for manual routine urinalysis. • Catheterised urine collection • Suprapubic transabdominal needle aspiration • Paediatric collection, with special polyethlene bags for collection • 24-hour urine collection. URINE COLLECTION METHODS
  12. 12. TYPES OF URINE SPECIMEN • FIRST MORNING SPECIMEN – obtained during the first urination of the day. Most concentrated, bladder incubated. Best for nitrite, protein and microscopic examination. • RANDOM SPECIMEN – obtained at any time during the examination. Most convenient, most common. Best for chemical screen and microscopic examination. • DOUBLE/SECOND-VOIDED URINE – in this case, first morning specimen discarded and the second specimen collected and test. Best for reflection of blood glucose and keeping of formed elements intact.
  13. 13. TYPES OF URINE SPECIMEN • POSTPRANDIAL – a specimen obtained 2 hours after meal. Good for glucose estimation. • 24 HOUR SPECIMEN – obtained within 24 hours. Necessary for quantitative test, especially for quantitative determination of protein. • MID-STREAM SPECIMEN – obtained from the middle part of the first urine. Best for routine urinalysis, also important for bacteriological urine culture.
  14. 14. TYPES OF URINE SPECIMEN CLEAN CATCH SPECIMEN – this is the best method used for microbial culture and routine urinalysis. This method is collected as follows: • The genital area should be cleaned with soap and water and rinsed well in other to keep off bacteria on the skin from contaminating the specimen. • The patient should urinate a small amount and this is discarded. • The urine that comes next, the mid-stream, should be collected into a sterile container of 30 to 50mls • After collecting the needed amount, the patient continues to urinate and this discarded.
  15. 15. URINE COLLECTION INSTRUCTIONS Garbage in, garbage out therefore the instructions are very vital. There will be different instructions for the same test based on: • Medical history • Diagnosis (presumptive or confirmed) • Age • Medical condition. • Record time of urine collection and receipt at lab
  16. 16. SOURCES OF ERROR IN THE COLLECTION OF URINE • Bacteriologically or chemically contaminated specimen • Wrong type/amount of preservative • Partial loss of specimen or inclusion of two-morning specimen in the 24-hour collection • Inadequate mixing of specimen before examination • Careless measuring of the 24-hour volume.
  17. 17. URINE STORAGE AND VIABILITY Long standing of urine at room temperature can cause: • Growth of bacteria • Break down of urea to ammonia by bacteria leading to an increase in the ph of the urine and this may cause the precipitation of calcium and phosphates. • Oxidation of urobilingen to urobilin. • Usage of glucose by cellular elements • Lysis of RBCs, WBCs and casts
  18. 18. METHODS OF PRESEVATION OF URINE SPECIMEN PHYSICAL METHOD • Refrigeration • Freezing CHEMICAL METHOD Use of chemical preservatives such as: • Thymol • Toluene • Formaldehyde • Hydrochloric acid • Chloroform • Boric acid • Chlorhexidine • Sodium carbonate
  19. 19. URINALYSIS Urinalysis requires 2 broad types of examination: 1. MACROSCOPY • Direct visual observation to note colour, appearance, odor and consistency. • Dipstick analysis: tests include pH, specific gravity, protein, glucose, ketones, nitrite, and leukocyte esterase etc. 2. MICROSCOPIC ANALYSIS • Sediment is examined for red blood cells, white blood cells, epithelial cells, casts, bacteria, yeast, and crystals, and others using the microscope.
  20. 20. PROCEDURE • Gather and check expiry dates of reagents or strips, perform hand hygiene and put on PPE’s • Confirm patients labelled information; name, age, dob, path number etc • Inspect colour by picking the specimen container up and bring it to the eye level as much as possible. • Inspect clarity and assess urine odour • Gently swirl specimen container • Remove test strip and immerse into urine ensuring that all zones are immersed.
  21. 21. PROCEDURE CONT’D • Remove test strip and ensure that excess urine is removed. • Place strip on a horizontal orientation to avoid cross contamination of zones. • Inspect each test at the appropriate time interval using the dipstick analysis chart. • Discard strip, perform hand hygiene and document the results
  22. 22. Dipstick analysis
  23. 23. MACROSCOPY – COLOUR AND APPEARANCE • Normal urine colour is often described as straw, yellow or amber. Urochrome pigment is mainly responsible for normal urine colour. This colour may be altered by medications, food sources or disease. • Vitamin tablets often result in a bright yellow urine, as does the presence of bilirubin (a bile pigment). Blood stained urine may be due to blood, haemoglobin, or beetroot. Iron supplements may cause a dark brown specimen • Normal urine is also transparent/clear. Turbid or cloudy urine may result from infection, the presence of blood cells, bacteria or yeast (eg candida) etc • Other common causes of urine turbidity: a. Semen, or vaginal discharge mixed with urine. Urine specimen, standing for long period on the bench, will become hazy or cloudy due to precipitation of crystals. • MACROSCOPY IS CLOSELY RELATED TO MICROSCOPY.
  24. 24. MACROSCOPY – pH • It is important that a fresh sample be used as urine becomes more alkaline over time as bacteria convert urea to ammonia (which is very alkaline). • Low pH (acidic urine) are caused by foods such as acidic fruits and other causes include diabetes and starvation. • High pH (alkaline) can be associated with low carbohydrate or vegetarian diet, renal calculi. Or urinary tract infection
  25. 25. MACROSCOPY – SPECIFIC GRAVITY • This measures the kidney's ability to concentrate or dilute urine in relation to plasma by comparing the weight of urine (particles) to the weight of distilled water (1.000). • Usually, 1.015 with normal fluid intake. • Increased SG may be due to dehydration or an increased secretion of anti-diuretic hormone (ADH) • Decreased SG may be due to; excessive fluid intake (oral or iv fluids), renal failure, acute glomerulonephritis, pyelonephritis, acute tubular necrosis, diabetes insipidus
  26. 26. MACROSCOPY – PROTEIN • Normally, urine is free of protein or has only a trace. • Proteinuria occurs with renal disease. • While both albumin and globulin may be excreted in the urine, albumin filters more readily than globulin, so protein in the urine is primarily albumin. • The first indication of renal disease is often the finding of small amounts of albumin in the urine (microalbuminuria)
  27. 27. MACROSCOPY – KETONES They are produced during fat metabolism. Ketones may be present in the following conditions: • Diabetes • Alcoholism • A state of starvation and pregnancy.
  28. 28. MACROSCOPY – BILIRUBIN • Presence of bilirubin in the urine may indicate - Liver disease, - Biliary tract infection - Pancreatic causes of obstructive jaundice. • Note that urine containing bilirubin will typically be red-brown in color and produce a yellow foam when shaken. • Bilirubin is not stable in solution, and when there is a delay in the analysis it will be oxidized to biliverdin, which is a green pigment when exposed to light
  29. 29. MACROSCOPY – UROBILINOGEN • Normally 1-4 mg of urobilinogen is excreted in the urine each day. • Urine is often tested for increasing urobilinogen when investigating haemolytic jaundice or liver disorder in which liver function is impaired.
  30. 30. MACROSCOPY – BLOOD/HAEMOGLOBIN • Hemoglobin appears in the urine when there is extensive or rapid destruction (hemolysis) of circulating erythrocytes that the reticuloendothelial system cannot metabolize or store the excessive amounts of free haemoglobin. • Hemoglobinuria is usually related to hematuria- a condition when intact red blood cells are present in the urine. • Red cells rapidly lysis in urine, especially when it has a specific gravity of 1.006 or less or is alkaline. • It may be present as a result of hemolysis in the blood stream, in a particular organ, in the kidney of lower urinary tract.
  31. 31. MACROSCOPY – LEUCOCYTES • Detects white cells in the urine (pyuria) which is associated with urinary tract infection. • False positive may occur if the dipstick has been exposed to air for a long period, the specimen is contaminated with vaginal secretions, or the patient is taking phenazopyridine. • False negatives can occur with increased specific gravity, decreased ph (<6.0), increased urobilinogen, and vitamin c
  32. 32. MACROSCOPY – NITRITE • The detection of nitrite in the urine can be used to indicate the presence of bacteria such as escherchia coli, proteius, klebsiella, enterobacter, citrobacter, and salmonella will reduce urinary nitrate to nitrite • Detection rate of nitrites increases when the urine is held in the bladder for at least 4-6 hours, test for nitrite may therefore be performed on a first morning urine specimen if it is strongly suspected but it tests negative in a random sample
  33. 33. MACROSCOPY – GLUCOSE • Glucose is not normally present in the urine. • Once the level of glucose in the blood reaches a r̃enal threshold, the kidneys begin to excrete it into the urine in an attempt to decrease the blood concentration. • Glucosuria is associated with conditions like: diabetes, liver disease, hyperthyroidism, medications such as tetracycline, lithium, penicillin, cephalosporins, pregnancy
  34. 34. MICROSCOPY • A microscopic examination of urine sediment detects the presence and amounts of: cells, microorganisms, spermatozoa, mucus, casts, crystals. • Particles of nephrological importance in microscopy - cells - lipids - casts - crystals - microorganisms
  35. 35. THANK YOU