Copyright 2004, Medicine School of Shandong University 1 Platelet Count Test Institute of Diagnostics Zhong Ning Email: [email protected]

Copyright 2004, Medicine School of Shandong University 1

Platelet Count Test

Institute of Diagnostics

Zhong Ning

Email: [email protected]


Platelet Count


• 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


Definition

• This is a test to measure the number of platelets in blood

• Platelets are necessary for normal blood clotting (hemostasis).


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.


Neubauer Chamber Improved




Clinical Significance of Platelet Count

Increase Platelet Count (Trombocytosis)• Malignant tumor• Polycythemia vera• Splenecytomy


Low Platelet Count (Thrombocytopenia)• ITP ( idiopathic thrombocytopenic purpura)• Acute mass loss of blood• AIDS• Hemolytic Disorders• Hypersplenism ( overactive spleen )• Administration of Heparin


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).

Owner

Resin from wood of certain species of GUAIACUM. It is used as clinical reagent for occult blood.

Owner

Hemoglobin Oxidation


Reference Value

• Healthy person is negative


Clinical Significance of OB

Positive:

UGB : upper gastrointestinal bleeding

Such as: Gastric ulcer

Hepatic cirrhosis gastric mucosa bleeding

Owner

fundus of stomach have varicose vein.


False-Positive• Red meat • High-fiber diet


Microscopic examination

• Cellular elements: erythrocytes

leucocytes

epithelial cells• Casts: • Crystals:

Brightfield microscopy can be performed unstained urine preparation


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


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”.


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


Leukocytes in urine

• In fresh specimen, leukocytes appear as granular spheres with multilobated nuclei

• Leukocytes degenerate, nuclear detail may be lost


Epithelial cells

• Renal tubular epithelial cells• Transitional (urothelial) epithelial cells• Squamous epithelial cells


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


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


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


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


Casts

• The factors which favor protein cast formation are low flow rate, high salt concentration, and low pH (favor protein denaturation and precipitation)


Casts

• The protein forms a meshwork that trap any elements present in the tubular filtrate including cells, cell fragments, or granular material


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


Hyaline casts

• Translucent

• In normal urine, 0~2 hyaline casts/lpf

• Increased numbers --- renal disease or transiently with exercise, fever, congestive heart failure


Cellular casts

• Erythrocyte (RBC) casts• Leukocyte (WBC) casts• Renal tubular epithelial cell casts


RBC casts

• Red blood cells stick together in the cast

• RBCs casts are indicative of glomerulonephritis or severe tubular damage (severe pyelonephritis)


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


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


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


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


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.


Crystals in normal urine

• Calcium Oxalate Dihydrate crystals

• Calcium Oxalate Monohydrate crystals



• Triple phosphate crystals



• Uric acid crystals


Crystals in abnormal urine

• Sulfadiazine crystals are a common finding with administration of Trimethoprim-sulfadiazine.

Documents

Copyright 2004, Medicine School of Shandong University 1 Platelet Count Test Institute of Diagnostics Zhong Ning Email: [email protected]