Archive for the ‘Laboratory Procedures’ Category

The Cardiac Enzymes and Isoenzymes in Myocardial Infarction

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Posted 02 Mar 2013 — by admin
Category Clinical Chemistry, Diseases and Conditions, Laboratory Procedures

When a patient is suspected of having a Myocardial Infarction (M.I.), heart attack, or have had a heart attack, part of the common tests performed are the cardiac enzyme tests. These include CK2 (CKMB,) LD1, and AST. For the non-enzymatic substances, these include myoglobin, Troponin I and Troponin T.

CK2 or CKMB is an isoenzyme of Creatine Phosphokinase (CPK) which is specific for the heart. It is the second fastest-moving CK isoenzyme in electrophoresis.

LDH1 or LD1 is isoenzyme of Lactate Dehydrogenase that is significantly increased in Myocardial Infarction. It is the fastest moving isoenzyme of LD during electrophoresis.

AST is also elevated during M.I. because of its origin in the heart muscles. Together with CK2 and LD1, they could help doctors in the diagnosis of M.I.

Non-enzymatic panel tests are should be performed together with the enzymatic to provide more significant data.

The symptoms and other diagnostic tests of the patient should also be integrated when interpreting laboratory results.

The elevation of CK, AST and LD during a heart attack is that CK peaks first, then AST, and then LDH.

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Precautions in Specimen Collection for Routine Urinalysis

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Posted 26 Dec 2012 — by admin
Category Laboratory Procedures

Routine urinalysis is one of the common tests performed in the laboratory. Hence, it is crucial that even you, as the patient, learn the precautions in collecting your urine specimen for routine urinalysis.

medical technologist precautions urinalysis

medical technologist examining a urine specimen, Image credit: Camille Santos

Here are important precautions that you should observe.

Know if the test is, indeed, routine urinalysis.

There are other tests done on urine samples such as:

  • Creatinine clearance
  • 24-hr urine test
  • 12-hr urine test

Once you are sure that it is routine urinalysis, you can now request for a sterile urine or sample container from the lab aide or technologist. If the doctor ordered the test, then wait for the sterile specimen container from the lab aide.

    The best sample for routine urinalysis is the early morning urine sample.

After you wake up, collect your specimen in your container by washing your vagina properly first. The early morning urine is best because it contains more sediments than other samples.

    Do the midstream catch method.

After washing, you then discard the first portion of your urine, and then collect the midstream part.  This would prevent contamination from foreign or outside sources.

    Open only the specimen container when you are ready to collect your urine.

Just like precaution no. 3, this would prevent contamination of your urine sample from foreign sources.  You have to cover your sample immediately to prevent contamination.

    Preserve the integrity of your urine sample by preserving it properly.

The sediments in urine specimens could disintegrate or be destroyed if you do not preserve your specimen. You can do this by submitting your specimen immediately to the laboratory.

If this is not possible, then you should preserve your urine specimen by storing it at refrigerated temperatures. Your specimen should reach the laboratory within an hour. This is one of the major precautions in specimen collection for routine urinalysis.

    If you have menstruation, you should ensure that you have washed well, and that no blood has contaminated your sample.

You have to inform the medical technologist that you are menstruating. This would make him/her aware of the circumstances surrounding your urine collection.

    Label your specimen bottle with your complete name

Remember to label your specimen bottle correctly with your complete name, including your middle initials. You can do this using a pentel pen or a masking tape. The lab aide would label it as soon as you submit your sample but it would help a lot if you label the sample too.

Observing these precautions in the specimen collection for routine urinalysis would ensure accurate results obtained from your specimen.

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Causes of In-Vitro Hemolysis

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Posted 19 Jun 2012 — by admin
Category Clinical Chemistry, Laboratory Procedures

The causes of in-vitro hemolysis are many resulting from the specimen collection, to specimen processing and to specimen storage.

What is in vitro hemolysis?

In vitro hemolysis is the lysis or destruction of red blood cells (RBC) outside the body. The RBCs could either swell or shrink, destroying the RBC.

Here are some causes of hemolysis:

  • Using a smaller gauge than the standard. Ideal gauge of needle for venipuncture is usually 20-22. A gauge 25 needle is one significant cause of hemolysis, especially if blood specimens are handled roughly.
  • Squirting the blood directly into the specimen container.
  • Squirting the blood without removing the needle.
  • Using wet equipment, like wet syringes and wet test tubes.
  • Shaking the specimen vigorously.
  • Freezing the blood immediately after collection.

Hemolyzed serum should not be used in laboratory tests because it would yield unreliable results.

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What are the Differences between Serum and Plasma?

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Posted 19 Jun 2012 — by admin
Category Clinical Chemistry, Laboratory Procedures

Serum and plasma are types of blood specimens that are utilized in testing for the concentrations of substances in the blood. They are supernatant fluids obtained after centrifugation of clotted blood and noncoagulated blood, respectively.

Here are some differences between serum and plasma:

Category Serum Plasma
color light yellow lighter
transparency clearer than plasma less clear than serum
Serum protein present albumin, globulin albumin, globulin,  fibrinogen
anticoagulant absent present

Why is serum generally the most preferred blood specimen for clinical chemistry tests?

Serum is the preferred specimen because they have fewer proteins, which are considered as interfering substances for some tests.

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Glucose Determination -Ortho-toluidine Manual Method

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Posted 17 Sep 2011 — by admin
Category Clinical Chemistry, Laboratory Procedures

Precautions  for Glucose Determination (Ortho-Toluidine Method)

As presented by  kit procedure

1. Patient should have fasted for 8-12 hours.
2. Unhemoylzed, non icteric and non turbid serum should be used to avoid interferences
with the procedure.
3. The reagent contains sodium azide, which is corrosive, so PPE should be worn.
4. The solution should be brought to a boil to ensure proper reaction.

MANUAL PROCEDURE PROPER: ORTHOTOLUIDINE  METHOD

1. Prepare Three tubes labeled, SA (Sample)/ C (Control), ST (Standard) and RB (Reagent Blank).

2. To the SA/C tube add 0.1 ml of the test specimen/ Control specimen.

3. To the ST tube add 0.1 ml of the standard stock solution.

4. To the RB tube add 0.1 ml of distilled water.

5. Add 4 ml of glucose reagent to all tubes. Cap and mix by gentle inversion.

6. Boil all tubes at 100 degrees centigrade for 8 minutes.

7. Cool tubes in running tap water for about 2 minutes.

8. Read absorbance of solutions in the spectrophotometer with appropriate cuvets at 636 nanometers against the RB (Reagent Blank).

9. Compute for the Cu (Concentration of the Unknown making use of the formula:

Cu= Absorbance of Unknown(Au) multiplied by the Concentration of the
Standard(Cs) divided by the Absorbance of the Standard (As)

Adapt the unit of the Cs

Normal Values = 60 – 100 mg/dL
to convert values to mmol/L multiply values in mg/dL with 0.0555

Normal high can reach   as far  as  120 mg/dL

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Urinalysis: The Diagnostic Procedure

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Posted 16 Mar 2011 — by admin
Category Health Procedures, Keeping Healthy, Laboratory Procedures

Urinalysis is one of the most common diagnostic procedures or tests requested by doctors. This is probably because of the easy availability of specimen, ease of collection and relatively inexpensive cost of the test. However, the simplicity of the procedure should not be a reason for either the patient or medical technologist to be too lax about urinalysis. Although the test seems easy to do, it is one of the most useful diagnostic tools used by doctors to screen diseases. Here are some of the important things you must know about the test.

Illnesses Detected

Urinalysis detects various medical conditions. Since urine is an ultra filtrate of blood, it contains information about your body’s most important processes. The few amount of urine can help you diagnose possible kidney related problems such as urinary tract infection, renal stones and glomerulonephritis. It can also detect chronic conditions like diabetes mellitus. Usually, doctors request for urinalysis when you show symptoms like low back pain, painful urination, abdominal pain and blood in the urine. The diagnostic procedure is very useful in diagnosing urinary tract infections, UTI.

Patient Preparation

The patient preparation depends on the kind of urine specimen requested from you. However, the most common specimen required is the random and first morning specimen. Since random specimen may be taken anytime of the day, there are no special preparations needed. For the first morning specimen, you have to collect the urine upon waking up in the morning. This is more preferred as the various urinary constituents have been pooled overnight which represent a better view of the body’s metabolism. For both types, you need to do a “clean-catch mid-stream”. For ladies, wash the vaginal area prior to collection. Allow the few drops of urine to come out before collecting the middle part. Avoid contaminating the specimen with tissue paper or water.

Test

The actual urinalysis test will only take 10-15 minutes. During this time, the medical technologist will do a visual, chemical and microscopic examination. After the test, your doctor will then interpret the results with consideration of your medical history, signs and symptoms and results from other diagnostic procedures.

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Alternate Sites for Capillary Puncture

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Posted 13 Mar 2011 — by admin
Category Health Procedures, Laboratory Procedures

There are several alternate sites for capillary puncture. These alternate sites are also good alternatives when the designated puncture area is injured.

Capillary puncture is the collection of blood through the capillaries; hence, through the capillaries of the skin. The most common sites are the pads of the fingers.

Alternate sites include:

Ear lobes

Big toes

Heel of infants

These are alternate sites of puncture that you can take advantage of. Remember to wipe the first drop of blood before collection as this is contaminated with tissue juices. Knowing the correct procedure in collecting from these alternate sites will ensure the reliability of your laboratory results.

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Capillary Puncture: Important Things You Must Know

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Posted 08 Mar 2011 — by admin
Category Hematology, Laboratory Procedures

Capillary Puncture
Image Credit: aeonbox.com

There are different ways to draw blood from a patient and capillary puncture is one of them.  If you compare it with venipuncture and arterial puncture, it is the easiest way to obtain a blood specimen. Usually doctors request the procedure when there is minimal volume of blood needed. If you have a blood request stating capillary puncture in the laboratory request form, here are some basic information about the procedure.

Capillaries

Also known as the “finger stick”, the capillary puncture involves the smallest blood vessels in the body. Since the capillaries are found all throughout the body and in a more superficial location, it only involves poking the skin with a sharp object called a lancet.  The most common sites for specimen collection are the palmar surfaces of the fingers, ear lobe and big toe or heel for the infants. Once the blood starts to ooze from the punctured site, the medical worker will collect the specimen in a capillary tube or in an appropriate specimen container.

Preparation

There are no special patient preparations indicated for capillary puncture. In fact, it only requires minimal training to correctly perform the blood collection. Even non- health workers can obtain the blood provided that they have the necessary equipment and basic knowledge on the proper collection technique. Oftentimes, diabetic patients are the most common lay persons who perform the capillary puncture at home for their daily blood sugar monitoring.

Procedure

The principle in obtaining blood through capillary puncture is the same with venipuncture and arterial puncture. Of course, the health worker needs to correctly identify the patient and choose the most appropriate site. Highly calloused fingers or those with skin injuries like hematoma and bruises and edematous areas are not recommended. Once the health provider has settled with the site, he/she has to clean the site of puncture with a cotton and alcohol starting from the center moving outwards. Using a swift and deliberate motion, he/she will then puncture the skin with a lancet, wipe the first drop of blood and collect the blood using a capillary tube.

Precautions

During the collection, squeezing of the punctured must be avoided. It leads to dilution of blood with tissue juices, thereby leading to erroneous results. Since young children are the common patients indicated for capillary puncture, assistance from adults and use of restraining devices may be necessary. If your kids are the patients, you must help the health worker explain the procedure to your child. Be truthful about what to expect. Tell them about the minimal but tolerable pain that they will feel. Do not tell them it does not hurt, because it does. Reassure them though that the pain is tolerable.

Aftercare

Since capillary puncture involves a minor puncture, there are no known health risks for it, if performed by knowledgeable personnel. However, you must apply pressure to the site for 3 to 5 minutes to stop the bleeding. The whole procedure only takes up to 5 minutes to complete. After the capillary puncture, you can always go back to your regular activities.

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Things you Must Know about Pap Smear

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Posted 12 Dec 2010 — by admin
Category Histopathology, Laboratory Procedures

By Engracia S. Arceo, MPH, RMT

Papanicolaou test or also known as pap smear is a screening test for cervical cancer. The procedure gathers the cells in the cervix and uses them to detect abnormalities. It is an effective way to check for early changes in the integrity of cells. Because it is cheap and simple, it is widely available in most health care facilities in different countries.

Who Should be tested?

The test is highly recommended to all women belonging to the age group 21 to 65. If you had vaginal intercourse earlier, you do not have to wait to reach 21 years old. It is done on a regular basis especially during the reproductive year. Some organizations recommends that it should be done every 5 years or more often depending on the results of the previous test.

Are there Special Preparations?

To increase the accuracy of the test, most doctors recommend that you have your pap smear after your menstruation. Two days before the test, you should avoid douching or vaginal intercourse. If you are using vaginal creams, you should also notify your doctor.

How Long is the Procedure?

The specimen collection will only take 3 to 5 minutes. The doctor will use a speculum to widen the opening of the vagina. The procedure may cause a slight discomfort. After the collection, the smear will be sent to the laboratory for processing.

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Cervical Cancer- Protect Yourself

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Posted 11 Dec 2010 — by admin
Category Diseases and Conditions, Histopathology, Laboratory Procedures

By Engracia S. Arceo, MPH, RMT

Cervix refers to the lower part of the uterus. When problems in the cervix arise, the symptoms are so general that they go unnoticed. If you are a woman aged 18 years old and above and is sexually active, it is imperative that you undergo pap’s smear to see whether you have the deadly disease. Here are some facts about cervical cancer.

Symptoms

Some patients who have cervical cancer do not present any sign of the illness. However, in most women, the common symptoms can include abnormal vaginal bleeding, unusual heavy discharge, and pelvic pain, pain during urination and pain and bleeding during a sexual intercourse. In rare cases, infections are also present.

Diagnosis

The use of symptoms alone cannot diagnose cervical cancer. For the preliminary assessment, your doctor may request a pap’s smear to check for the integrity of the individual cells. Usually, cancerous cells present themselves well under the microscope. If you get a positive Pap’s smear test, further testing is required.

Treatment

Women positively diagnosed with cervical cancer have many options for treatment. Surgery, radiation therapy, chemotherapy or a combination of all of these may be warranted. If you have questions about the treatment, you should always ask your doctor about it.

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