copyright 2004, medicine school of shandong university 1 platelet count test institute of...
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Copyright 2004, Medicine School of Shandong University 1
Platelet Count Test
Institute of Diagnostics
Zhong Ning
Email: [email protected]
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Platelet Count
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• Platelets are manufactured in bone marrow by megakarocyte.
• Platelets are only fragments of ctyoplasma.• They are removed by spleen when they are
old or damage.
Reference value
150,000~350,000/㎜ 3
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Definition
• This is a test to measure the number of platelets in blood
• Platelets are necessary for normal blood clotting (hemostasis).
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Performance
1. Blood is drawn from a vein, usually on inside of the elbow or the back of the hand , or fourth finger.
2. A needle is inserted into the vein, and the blood(20ul) is collected in a tube with platelet dilution(0.38ml).
3. A drop of Platelet suspension added into the Neubauer chamber.
4. Count.
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Neubauer Chamber Improved
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Clinical Significance of Platelet Count
Increase Platelet Count (Trombocytosis)• Malignant tumor• Polycythemia vera• Splenecytomy
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Low Platelet Count (Thrombocytopenia)• ITP ( idiopathic thrombocytopenic purpura)• Acute mass loss of blood• AIDS• Hemolytic Disorders• Hypersplenism ( overactive spleen )• Administration of Heparin
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Occult Blood Test
• Occult Blood (OB) means Hidden blood that can’t easily been found the presence of blood.
• Sometimes it is called Guaiac Test• Gastroccult is specifically designed to test
for occult blood.• This test always is used to test the feces (sto
ol).
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Reference Value
• Healthy person is negative
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Clinical Significance of OB
Positive:
UGB : upper gastrointestinal bleeding
Such as: Gastric ulcer
Hepatic cirrhosis gastric mucosa bleeding
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False-Positive• Red meat • High-fiber diet
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Microscopic examination
• Cellular elements: erythrocytes
leucocytes
epithelial cells• Casts: • Crystals:
Brightfield microscopy can be performed unstained urine preparation
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Erythrocytes
• In normal urine, less than 3RBCs/hpf • More than 3RBCs/hpf is abnormal• Causes: 1. renal diseases: glomerulonephritis, calculus, tumor 2.urinary tract diseases: acute and chronic infection, calculus, tumor, hemorrhage cystitis 3. toxic reactions due to drugs: anticoagulant therapy
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RBCs in urine
• Normally, RBCs appear as pale biconcave disks.
• In hypertonic urine, RBCs become crenated.
• In dilute urine, RBCs lyse and left only empty cell membranes refer to as “ghost cells”.
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Leukocytes
• The predominant type of leukocyte is the polymorphonuclear leukocyte (neutrophils)
• In normal urine, less than 5 leukocytes/hpf• Pyuria---more than 5 leukocytes/hpf • Causes: urinary tract infection such as
pyelonephritis, cystitis, urethritis
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Leukocytes in urine
• In fresh specimen, leukocytes appear as granular spheres with multilobated nuclei
• Leukocytes degenerate, nuclear detail may be lost
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Epithelial cells
• Renal tubular epithelial cells• Transitional (urothelial) epithelial cells• Squamous epithelial cells
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Renal tubular epithelial cells
• In normal urine, small numbers of these cells may be seen
• Increased number indicates tubular damage, such as acute tubular necrosis or certain drug toxicity
• Larger than leukocytes with a large round nucleus
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Transitional (urothelial) epithelial cells
• Line the urinary tract from the pelvis to the bladder
• In normal urine, a few these cells may be seen
• Increased numbers of cells suggest urinary tract disorders such as infection, calculus
• Cells larger but nucleus smaller than renal tubular epithelial cells
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Squamous epithelial cells
• From urethra
• most frequent epithelial cells seen in normal urine
• Large clumps suggest urethritis
• Large and flat with abundant cytoplasm and small round nuclei
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Casts
• Formed only in the distal convoluted tubule (DCT) or the collecting duct
• Tamm-Horsfall protein (T-H glycoprotein) forms the matrix of all casts
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Casts
• The factors which favor protein cast formation are low flow rate, high salt concentration, and low pH (favor protein denaturation and precipitation)
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Casts
• The protein forms a meshwork that trap any elements present in the tubular filtrate including cells, cell fragments, or granular material
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Casts
• Very few casts are seen in the urinary sediment
• Increased numbers or different forms of casts indicate that kidney disease is widespread
• Casts may be classified according to their matrix, inclusion and cell present
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Hyaline casts
• Translucent
• In normal urine, 0~2 hyaline casts/lpf
• Increased numbers --- renal disease or transiently with exercise, fever, congestive heart failure
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Cellular casts
• Erythrocyte (RBC) casts• Leukocyte (WBC) casts• Renal tubular epithelial cell casts
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RBC casts
• Red blood cells stick together in the cast
• RBCs casts are indicative of glomerulonephritis or severe tubular damage (severe pyelonephritis)
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WBC cast
• White blood cells stick together
• WBC casts’ presence indicates inflammation of the kidney.
1. The most common disease--pyelonephritis
2.Also present with glomerulonephritis
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Renal tubular epithelial cell casts
• The most reliable distinguishing characterize is their singular round nuclei
• These casts’ presence suggests tubular injury, such as acute tubular necrosis, exposure to some drugs
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Granular casts
• Granules may originate from plasma protein aggregates or from cellular remnants of WBCs, RBCs, and damaged renal tubular cells
• Granular casts’ presence---chronic renal disease
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Waxy casts
• Homogeneously smooth with sharp margins, blunted ends and cracks along the margins
• Reflect the final phrase of dissolution of the granular casts
• waxy casts most frequently in patients with chronic renal failure
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Crystals
• Form by the precipitation of urinary salts. • In vivo, increased solute concentration is
typically responsible for crystal formation.• Most crystals in the urine are of limited
clinical significance. • Proper identification of few abnormal
crystals is associated with various pathologic conditions.
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Crystals in normal urine
• Calcium Oxalate Dihydrate crystals
• Calcium Oxalate Monohydrate crystals
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Crystals in normal urine
• Triple phosphate crystals
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Crystals in normal urine
• Uric acid crystals
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Crystals in abnormal urine
• Sulfadiazine crystals are a common finding with administration of Trimethoprim-sulfadiazine.