Posts Tagged ‘Laboratory Specimens’

ROUTINE URINALYSIS

3 Comments
Posted 30 Sep 2010 — by admin
Category Clinical Microscopy, Laboratory Procedures

By: Lou Grace T. Manalili, RMT, DVM

Two general standpoints may be considered in the routine urinalysis. First is for the management and diagnosis of renal or urinary tract disease and second, the detection of systemic or metabolic diseases indirectly to the kidney.

Routine urinalysis is composed of four parts:

  • SPECIMEN EVALUATION – this implies specimen acceptability. Proper specimen labeling, proper use of preservative and any transportation delays in getting the specimen to the laboratory are some considerations to consider.
  • PHYSICAL TESTS – these include color, odor, volume, osmolality and specific gravity of urine.
    • Color- urochrome is a pigment responsible for the normal color of urine that varies from pale yellow to amber and this is also due to small amounts of pigments uroerythrin and urobilins. Any abnormalities in color maybe a cause of a renal disease or just a physiologic cause from food intake or medicine.
    • Odor – faint aromatic scent is normal, a change in odor like foul or ammoniacal indicates bacterial contamination.
    • Volume – adult daily average volume of urine ranges from 1.2 Liters to 1.5 Liters.
    • Osmolality –500 to 850 mOsm/kg of urine will be produced by an individual in a regular diet taking 8 to 10 glasses of water a day.
    • Specific gravity – this varies from 1.016 to 1.022 during a 24-hour period.
  • CHEMICAL EVALUATIONS
    • pH in urine – this is an indication of the capability of the kidney to sustain normal hydrogen ion concentration in plasma and extracellular fluid.
    • Protein – occurrence of this in urine may arise after a tough exercise or dehydration or patients with urinary tract infection, hemorrhage or with fever.
    • Glucose – in a typical urine sample, glucose is absent but this maybe present in the urine if blood glucose level exceeds 180 to 200 mg/dl.
  • SEDIMENT EXAMINATION – this is done through the use of a microscope and usually for the detection of diseases of the kidney. Presence of casts, increase amount of pus cells, blood cells or bacteria indicate urinary tract infection and/or a renal disease.

Routine urinalysis also has two major components: the macroscopic and the microscopic testing. Available reagent strips are being used for the macroscopic examination that includes the chemical and physical tests of urine.

  • Steps for Macroscopic Routine Urinalysis
  1. Examine and evaluate urine specimen. Properly label, indicate name, age, gender of owner and record time received, volume and color.
  2. Pour 10-15ml of urine in a centrifuge tube and take note on the report if the volume is less than the required volume.
  3. Determine transparency or clarity as to clear, slightly turbid or turbid.
  4. Determine specific gravity, pH, glucose and protein with the use of reagent strips. Compare strips to color chart and record results.
  5. Prepare urine specimen for microscopic test.
  • Steps for Microscopic Routine Urinalysis
  1. Centrifuge urine sample of 10-15ml in a tube for about 5 minutes.
  2. After centrifugation, carefully tilt the tube bottoms up to separate sediments from the supernatant. Save the supernatant for possible retesting.
  3. Gently suspend the sediment on a glass slide and place a cover slip on top of it.
  4. Examine under low power objective in at least 10 low power fields sediments with low refractive index like, epithelial cells, mucus threads, urates, casts, crystals and bacteria. Report as few, moderate or many.
  5. Red blood cells and pus cells are identified and counted under a high power objective in at least 10 high power fields. Report as cell/hpf.
  6. Comment and take note for presence of large amount of crystals, bacteria, yeast or any microorganism. Perform confirmatory test if needed.

Review results, make a report on the test then affix your signature on the form to determine examiner.

Tags: , ,

The Venipuncture Procedure

No Comments
Posted 23 Feb 2010 — by admin
Category Laboratory Procedures

The venipuncture or phlebotomy procedure is one method of blood collection that allows multi-collection with a larger volume of blood.  You can do it with the use of a syringe or a vacutainer whichever you find easier. Not anyone can perform a venipuncture because of some complications that can occur in the process.  Skilled phlebotomists or Medical Technologists usually perform the procedure.

photo by Fatima Al Ribh

Materials needed

Sterile and dry syringe

Sterile dry cotton

Sterile wet cotton

Test tubes

Needle

Test tube rack

Labeling tape

Pentel pen or labeling pen

Parafilm

Tourniquet

Procedure

Step 1

Prepare your materials by arranging them in an area within your arm’s reach. Check the needle and syringe if they are working well, by pulling and pushing the plunger and examining the needle. Do not remove the cap of the needle unnecessarily.

Step 2

Select the most appropriate site of puncture. A vein that is not too small or too big is ideal. Big veins have the propensity to roll and small veins are less likely visible.  Take time in your selection process. The most common site of puncture is the antecubital fossa at the bend of the arm.  There are three veins you could select from, the cephalic, basilica and mid-cubital veins.

Step 3

When you have selected the best vein, sterilize it in a circular motion, starting from the site of puncture going outwards.  Do not reuse dirty cotton. Sterilize until clean.

Step 4

Let it dry for a few seconds and with your syringe and needle, puncture the site smoothly and deliberately.  There should be no hesitation, as this would inflict more pain to the patient. Enter the vein in one smooth movement.

Step 5

As blood enter the hub of the needle, pull the plunger smoothly taking care not to pull the needle out of the vein.

Step 6

After you have drawn the required amount of blood, withdraw the needle smoothly, not too fast, nor too slow to avoid severing the vein.

Step 7

Apply pressure to the wound for about 3-5 minutes.  You could allow the patient to do it, if he cannot, then apply micropore.  Be sure to check the wound after 5 minutes to make certain that there is no bleeding.

Step 8

Remove the needle from the syringe and transfer the blood to a test tube by allowing the blood to flow at the sides of the tube to avoid hemolysis. Be sure that your test tube is also dry and clean to avoid hemolysis and contamination. Cover the tube and label it properly.

Step 9

Dispose your used materials properly into appropriate trash bags or cans. Clean your working area properly,

Step 10

Check the wound of the patient and thank him/her for cooperating.

Tags:

Tips on Preventing Hemolysis

No Comments
Posted 22 Feb 2010 — by admin
Category Clinical Chemistry, Hematology, Serology and Immunology

In the laboratory, it is crucial that the clinical laboratory scientist performs the tests reliably, because the doctor bases his diagnosis on these laboratory results. Any source of error therefore is eliminated to ensure that all results are accurate. One source of unreliable results is hemolysis.   Hemolysis is the destruction or rupture of red blood cells (RBCs) causing the release of hemoglobin.   An indication of hemolysis is a pink colored serum or plasma.

Here are pointers to avoid hemolysis in blood samples.

1. Do not use wet materials because water is a hypotonic solution that causes lysis of RBCs.

2. Do not squirt blood directly into the test tube. The rapid flow may cause hemolysis. Allow the blood instead to ooze at the sides of the tube.

3. Remove the needle before transferring the blood to appropriate containers, the small opening of the needle may cause hemolysis.

4. Do not centrifuge blood if it still has not clotted properly.

5. Do not rim or ring the blood several times. This is one major source of hemolysis.

6. Do not freeze whole blood right after collection.

7. Do not vigorously shake whole blood, to avoid hemolysis in blood samples.

8. Do not expose the whole blood specimen to excessively low and hot temperatures.

9. Do not prolong tourniquet application more than necessary.

10.  Transfer the serum immediately to a different container to reduce the propensity for hemolysis.

11.  Do not pull the plunger too quickly. If the bore of the needle is small, it may cause hemolysis

12.   Allow the site to dry first after sterilization.  The alcohol still present in the area may come in contact with your sample and may produce hemolysis.

13.  There should be a proper angle of the needle to the vein to avoid transfixation, which may cause hemolysis.

14.  Any application of mechanical trauma or pressure on the blood sample will cause hemolysis, whether during collection, processing, or transportation.

Avoid hemolysis in blood samples at all cost, as this would produce unreliable results.  Unreliable results would lead to misdiagnosis. Misdiagnosis by the doctor because of your inaccurate results would endanger the life of the patient.  Remember these pointers on how to avoid hemolysis in blood samples and feel confident and secure that you are giving out your best service to patients.  Consider each patient as an important individual who deserves to  receive reliable results.

Tags: