Biochem-Lab-Blood-and-Urine-Analysis

BLOOD

• Blood is a type of connective tissue specialized with a matrix colloidal liquid and a complex constitution.

  1. Cellular component (solid phase): erythrocytes (or red blood cells), leukocytes (white blood cells), and platelets.

  2. Serum component (liquid phase): blood plasma.

• Plasma: the liquid part of blood. A dilute solution of salts, glucose, amino acids, vitamins, urea, proteins, and fats.

• White blood cells: involved in the immune system.

• Platelets: involved in blood clotting.

• Red blood cells: involved in carrying oxygen.

• About 7-8% of the total body weight is blood.

• An average-sized man has about 5.7 L of blood.

• An average-sized woman has 4.3 L of blood.

PLASMA

• The liquid component of the blood composed of a mixture of water, sugar, fat, protein, and salts.

• Plasma transports blood cells throughout the body along with nutrients, antibodies, clotting proteins, chemical messengers, and even waste products.

ERYTHROCYTES

• Erythrocytes or red blood cells (RBCs) are the most abundant cells in the blood, comprising about 40-45% of total blood volume.

• RBCs do not have nuclei and can change their shape to fit through various blood vessels.

• Their production is primarily controlled by erythropoietin, a hormone produced by the kidneys.

• The red blood cell survives on average only 120 days.

LEUKOCYTES

• Leukocytes or white blood cells (WBCs) are much fewer than RBCs, about 1% of the total blood.

• The primary role of WBCs is to protect the body from infection.

• They may come in many different shapes and sizes: have nuclei with multiple lobes, one large round nucleus, or have granulocytes.

NEUTROPHILS

• They are "immediate response cells" and make up 55-70% of total WBCs.

• They live less than a day; therefore, the bone marrow makes new neutrophils every day.

MONOCYTES

• They are young, immature WBCs that develop into macrophages after they migrate into the tissues.

• They provide an immediate defense through phagocytosis.

• Monocytes are also antigen-presenting cells, presenting the foreign antigen to other immune cells to trigger an immune response.

LYMPHOCYTES

• They are round cells that contain a single large round nucleus.

• B cells mature in the bone marrow and produce highly specific antibodies that bind to an antigen.

• T cells mature in the thymus gland and there are two types: helper T cells that secrete chemicals that recruit other immune cells, and cytotoxic T cells that attack virally infected cells.

PLATELETS

• Platelets are small fragments of cells that help in the blood clotting process by gathering at the injury site, sticking to the lining of the injured blood vessel, and forming a fibrin clot that covers the wound and promotes healing.

• A higher than normal number of platelets (thrombocythemia) can cause unnecessary clotting, leading to strokes and heart attacks.

MILLON'S TEST

• Detect the presence of tyrosine: a positive result shows a red color in the solution.

TESTS FOR WHOLE BLOOD TEST FOR CHOLESTEROL

• Acetic acid-sulfuric acid: a positive result indicates a hydroxyl group on the cholesterol and the unsaturated bonds on the adjacent fused ring, resulting in a green color of the solution.

TEST FOR IRON

• Potassium ferricyanide detects the presence of ferrous ion in the blood: a positive result shows Turnbull's blue.

TEST FOR BLOOD GASES

• Stoke's reagent detects the presence of oxyhemoglobin and reduced hemoglobin: a positive result changes the color of blood from bright red into a darker purple solution.

URINE

• Sterile liquid by-product of the body until it reaches the urethra.

• Often used as a diagnostic feature for many disease conditions.

• An aqueous solution greater than 95% water with urea, chloride, sodium, potassium, creatinine, and other dissolved ions, and inorganic and organic compounds.

• One of the waste products excreted through urine is urea, a processed form of ammonia that is non-toxic to mammals. It is produced to eliminate many cellular waste products and control water amount in the body (urine volume regulation) as part of homeostasis.

URINALYSIS

• Also known as routine and microscopy (R&M), is an array of tests performed on urine, one of the most common methods of medical diagnosis for urinary tract infections, kidney disease, and diabetes.

• When doctors order a urinalysis, they will request either a routine urinalysis (which does not include microscopy or culture) or a routine and microscopy (R&M) urinalysis, which is specifically used for culturing bacteria found in urine.

ANSWERS to QUESTIONS

WHAT IS THE DIFFERENCE BETWEEN OXYHEMOGLOBIN AND REDUCED HEMOGLOBIN?

• Oxyhemoglobin: Hemoglobin bound to oxygen, typically found in the lungs where oxygen concentrations are high. • Reduced Hemoglobin (Deoxyhemoglobin): Hemoglobin that has released its bound oxygen, typically found in tissues where oxygen concentrations are lower.

URINALYSIS

• Involves checking the appearance, concentration, and content of urine.

• A routine urinalysis usually includes the following tests: color, transparency, specific gravity, pH, protein, glucose, ketones, blood, bilirubin, nitrite, urobilinogen, and leukocyte esterase.

• Routine urinalyses are performed for several reasons: • General health screening to detect renal and metabolic diseases • Diagnosis of diseases or disorders of the kidneys or urinary tract • Monitoring of patients with diabetes.

• Routine urinalysis consists of three testing groups: physical characteristics, biochemical tests, and microscopic evaluation.

URINE SAMPLE COLLECTION

• 24-hour collection: patient voids into the toilet, then all urine is collected for the next 24 hours.

• First-morning specimen: first specimen of morning (or eight hours after recumbent position); best sample for pregnancy testing.

• Fasting specimen: the second voided specimen after a period of fasting.

• Mid-stream urine (MSU): used to obtain urine for bacterial culture; first and last part of urine stream is voided into the toilet to avoid contaminating the specimen with organisms present on the skin.

• Random specimen: for chemical or microscopic examination, a randomly collected specimen suitable for most screening purposes.

PHYSICAL TESTS FOR URINE

• Urine Color: Normal urine is straw yellow to amber in color. Red urine may be caused by blood or hemoglobin, beets, medications, and some porphyria. Black-gray urine may result from melanin (melanoma) or homogentisic acid (alkaptonuria, a result of a metabolic disorder). Bright yellow urine may be caused by bilirubin (a bile pigment). Green urine may be caused by biliverdin or certain medications. Orange urine may be caused by some medications or excessive urobilinogen. Brown urine may be caused by excessive amounts of prophobilin or urobilin (a chemical produced in the intestines).

• Transparency: Normal fresh urine is clear and transparent. Acid urine may produce white/pinkish sediments of amorphous ureates. Alkaline urine may produce white sediments of amorphous phosphates. Cloudy urine (Nubecula) appears after standing upon cooling due to the presence of mucus, leukocytes, and epithelial cells that settle.

• Urine Odor: The smell of urine may provide health information. The urine of diabetics may have a sweet or fruity odor due to the presence of ketones or glucose. Generally, fresh urine has a mild smell, and aged urine has a stronger odor similar to that of ammonia.

• Urine Density: A measure of the concentration of dissolved solutes (substances in a solution), reflecting the ability of the kidneys to concentrate the urine. Specific gravity is usually measured by determining the refractive index of a urine sample (refractometry) or by chemical analysis. Specific gravity varies with fluid and solute intake. It will increase (above 1.035) in persons with diabetes mellitus and after radiologic studies of the kidney owing to the excretion of radiologic contrast dye. Consistently low specific gravity (1.003 or less) is seen in persons with diabetes insipidus.

• Specific gravity reflects urine concentration: Normal: 1.008 - 1.030.

HIGH SPECIFIC GRAVITY: Dehydration, Glycosuria, Proteinuria, Radiographic contrast media.

LOW SPECIFIC GRAVITY: Compulsive water drinking, Diabetes insipidus, Renal failure.

BIOCHEMICAL TESTS FOR URINE

• Performed using dry reagent strips (dipsticks). The strip is dipped into urine, allowed to sit, and color is compared to a standard chart.

• Glucose: Normal: urine does not contain glucose. Abnormal: glycosuria; indicative of diabetes mellitus or pregnancy or patients taking corticosteroids.

• Ketone: Formed during abnormal breakdown of fat; may result from prolonged fasting, a diet, or poorly controlled diabetes (diabetic ketoacidosis).

• Blood: Normal: urine does not have blood; abnormal: hematuria, which can enter urine due to damage in the filtration barriers in kidneys or inflammatory lesions of the urinary tract.

• Protein: Normal: urine does not contain high levels of protein; abnormal: proteinuria, which can be caused by glomerular filtration barrier damage, kidney damage, or hypertension.

• Nitrite: Normal: urine does not contain nitrite; its presence indicates UTI but clinical symptoms must be observed.

• Leukocytes: Usually associated with UTI, but may indicate renal problems; presence indicates pyuria (pus in urine).

TEST FOR CREATININE

• Positive result: deep red color; indicates impaired kidney function or a lot of meat in the diet.

TEST FOR UREA

• Positive result: ammoniacal odor, gives a black deposit to filter paper with Nessler's reagent.

MICROSCOPIC TESTS FOR URINE

• Helps distinguish between a urinary tract infection and a contaminated urine sample by checking for presence of bacteria, yeast, and white blood cells.

• Presence of cellular casts and renal epithelial cells indicates kidney disease. Identifying normal and abnormal crystals in the sediment is significant as abnormal crystals indicate abnormal metabolic processes.

• Normal crystals are formed from normal metabolic processes but can lead to renal calculi (kidney stones).