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Laboratory Technique-2019

2nd Year Final Examination of Diploma in Medical Technology Course: January-2019
Group: Laboratory Medicine
Subject: Laboratory Technique (Paper-I)

Ans: Please see Jan-2020 (Q-4-a) and Jan-2021 (Q-5-b).

 Ans: Please see Jan-2021 (Q-2-e).



pH meter is an instrument by which pH can be measured most reliably and conveniently.

Use of pH meter: Measurement of pH of a solution.

Some common uses of pH meters:

  • Laboratory analysis: pH meters are essential tools in chemical and biological laboratories for measuring the pH of solutions used in experiments.
  • Water quality monitoring: pH meters are used to monitor the pH of drinking water, wastewater, and other bodies of water. 
  • Food and beverage production: pH meters are used in the production of food and beverages to ensure that products have the correct taste and texture.
  • Agriculture: pH meters are used in agriculture to measure the pH of soil and irrigation water. 
  • Pharmaceutical and biotechnology: pH meters are used in the pharmaceutical and biotechnology industries to measure the pH of drugs and other products. 


Definition of Enema :

An enema is an introduction of fluid preparation into the lower bowel through the rectum to remove the retained faecal matter from the sigmoid colon or to introduce medication or nourishment. 

Indications of Enema:

  • For the most part, people use enemas in order to treat constipation.
  • Removal of impacted faeces to fully evacuate the bowels when one is unable to evacuate normally.
  • Emptying the colon before medical procedure such as colonoscopy, X-ray of the colon to detect polyps surgery etc.
  • Beginning a program of bowel training.
  • As a vehicle for introducing drugs (including antibiotics and anti-seizure drugs).
  • Administration of fluids and nutrients.

Ans: Please see Jan-2021 (Q-1-d).

Ans: Please see Jan-2022 (Q-4-d).

Ans: Please see Jan-2021 (Q-2-c).

Ans: Please see Jan-2021 (Q-2-d).

Ans: Please see Jan-2021 (Q-1-e).

Ans: Please see Jan-2022 (Q-3-e).

Ans: Please see Jan-2021 (Q-1-c).


Uses of auto pipette (micropipette):

Auto Pipette is used to draw and dispense very smaller volumes of fluids less than 0.1ml accurately and precisely.

Use of Chemical Balance:

Chemical balance is used mainly to weigh the chemicals accurately for the preparation of quantitative reagents and standard solution.

Use of centrifuge Machine :

  • To obtain serum or plasma from red blood cells for antibody testing and clinical chemistry tests.
  • To sediment cells, bacteria, and parasites in body fluids for microscopic examination, e.g, blood, urine, cerebrospinal fluid.
  • To obtain serum, wash red cells, and perform emergency compatibility testing (cross matching).
  • To separate protein free filtrate.
  • To perform parasite concentration techniques.

Buffer solution:

A buffer solution is the one that resists changes in pH when small quantities of acid or alkali is added to it. A buffer solution contains a mixture of a weak acid and a salt of strong base, or a weak base and its salt with a strong acid.

Name some blood buffers.

Blood buffers:

  • In plasma :
  1. Bicarbonate buffer
  2. Phosphate buffer
  3. Plasma protein buffer
  • In RBC:
  1. Bicarbonate buffer
  2. Haemoglobin buffer
  3. Oxyhaemoglobin buffer
  4. Phosphate buffer

Importance of Blood Buffers :

In order to function properly, the human body needs to maintain a blood pH between 7.35 and 7.45. Any condition in which the blood pH drops below 7.35 is known as acidosis. If the pH rises above 7.45, it is known as alkalosis.

To prevent acidosis or alkalosis the body relies on the interaction of a chemical buffer system in the blood with the body’s respiratory and urinary systems.

Ans: Please see Jan-2021 (Q-1-a).

Definition of Haemolysis:

Haemolysis is the rupturing of red blood cells and the release of their contents into surrounding fluid (e.g. blood plasma) leading to a false increase in the concentration of analytes such as potassium.

Causes of haemolysis during blood collection:

  • Incorrect venipuncture technique.
  • Haemolysis of red cells 
  • Collection into the wrong container
  • Instability of some chemical substances in whole blood, serum, and plasma.


Use of high power lens/ objective (40X):

  1. Adjust the condenser about half way down.
  2. When the object is already adjusted on a low power objective, by using coarse adjustment raise the objective very slowly until a blurred image appears on the field.
  3. Bring the images into focus using the fine adjustment. Raise the condenser for sufficient illumination.

Care of microscope :

1. Examine all the parts of a microscope before use.

2. Keep the microscope in a perfectly clean condition.

3. Carry by holding the arm.

4. Clean the lenses with a Soft Cotton Cloth moistened with xylol. Remove xylol with a dry cloth without delay.

5. Clean the oil-immersion objective on each occasion after use, by wiping the oil from the front of the Lens with a cloth. 

Ans: Please see Jan-2021(Q-3-c).


The immediate management of burns is crucial to preventing further injury and complications. Here are some steps to follow:

  1. Remove the person from the source of the burn. This may involve turning off the heat source, removing the person from a burning building, or extinguishing their clothing.
  2. Cool the burn with running water for at least 20 minutes. This will help to stop the burning process and relieve pain.
  3. Cover the burn with a loose bandage or clean cloth. This will help to keep the burn clean and prevent infection.
  4. Elevate the burned area if possible. This will help to reduce swelling.
  5. Give the person over-the-counter pain relievers, such as ibuprofen or acetaminophen.
  6. Seek medical attention immediately for severe burns. This includes burns that are larger than 3 inches in diameter, burns that are deep or charred, burns that are on the face, hands, feet, or genitals, and burns that are caused by chemicals or electricity.

Here are some additional tips for managing burns:

  • Do not apply ice to the burn. This can damage the tissue and make the burn worse.
  • Do not break blisters. Blisters help to protect the burned area from infection.
  • Do not apply butter, oil, or other ointments to the burn. These can trap heat and make the burn worse.
  • Do not give the person caffeine or alcohol. These substances can dehydrate the person and make the burn worse.

Definition of anticoagulants:

These are chemical substances which prevent coagulation of blood. (Anticoagulant  হচ্ছে কতগুলি chemical substance যা ব্লাডের coagulation বা জমাট বাধা প্রক্রিয়াকে প্রতিরোধ করে।)

Classification of Anticoagulants:

Anticoagulants are classified in two groups:

A. In vitro (outside the body) anticoagulants – 

  1. EDTA (Ethylene Diamine Tetra-acetic Acid)
  2. Double oxalate (Paul-Heller mixture)
  3. Sodium citrate
  4. Potassium oxalate
  5. Heparin
  6. ACD and CPD-A mixtures

B. In vivo (in the body) anticoagulants-

  1. Heparin 
  2. Dicoumarol derivatives, e.g. warfarin.

Uses of Anticoagulants:

  1. EDTA: It is best for platelet count.
  2. Double oxalate: Can be used for haematological investigations (except clotting time and bleeding time) and biochemical tests (except blood urea) where whole blood or plasma is used.
  3. Sodium citrate: It is used for ESR determination by Westergren method and coagulation studies (e.g. prothrombin time, partial thromboplastin time).
  4. Potassium oxalate : It is used for biochemical tests (e.g. plasma glucose).
  5. ACD (acid citrate dextrose) and CPD-A (citrate phosphate dextrose-adenine) are the anticoagulants of choice for storage of blood in blood bags.
  6. Heparin, Dicoumarol and Warfarin: are clinically used to prevent intravascular clotting of blood.


A throat swab is a medical procedure that involves collecting a sample of cells from the back of the throat. This is done using a sterile cotton swab, which is inserted into the throat and rubbed against the tonsils and the back of the pharynx. The swab is then removed and placed in a tube containing a special transport medium. The tube is then sent to a laboratory for testing.

Throat swabs are used to diagnose a variety of conditions, including:

  • Strep throat
  • Influenza
  • Mononucleosis
  • Other viral and bacterial infections
  • COVID-19

How to prepare for a throat swab:

There is no special preparation required for a throat swab. However, you should avoid eating or drinking anything for at least 30 minutes before the procedure. This will help to ensure that the results of the test are accurate.

Hazard of throat swab collection:

  • Gagging or coughing
  • Minor discomfort or bleeding
  • Infection (rare)

Definition: The sphygmomanometer is an instrument routinely used for recording arterial blood pressure in humans. Commonly, it is called the ‘BP apparatus’.


A sphygmomanometer is a device used to measure blood pressure. It consists of an inflatable cuff, a measuring unit (the mercury manometer or aneroid gauge), and a mechanism for inflation which may be a manually operated bulb and valve or a pump operated electrically.

Types of sphygmomanometers:

There are two main types of sphygmomanometers:

  1. Mercury sphygmomanometer. 
  2. Aneroid sphygmomanometer. 

Parts of Sphygmomanometer: 

It consists of the following parts –

  • Mercury Manometer 
  • Graduated tube
  • Cuff (armlet)
  • Air pump (rubber bulb)

How to use a sphygmomanometer:

To use a sphygmomanometer, you will need to:

  1. Wrap the cuff around the upper arm, above the elbow. The cuff should be snug but not too tight.
  2. Inflate the cuff until the pulse in the arm disappears.
  3. Slowly release the air from the cuff while listening with a stethoscope for the Korotkoff sounds. The first sound you hear is the systolic pressure, and the last sound you hear is the diastolic pressure.

Use: Recording of arterial blood pressure in humans.


Autoanalyzer is an automated instrument / machine with which a large number of samples can be analyzed.Autoanalyzer may vary from semi to fully automated analyzers.

Use in Clinical Chemistry:

Autoanalyzers are used to determine levels of the following biochemicals in the blood and other body fluids –

  • Glucose
  • Lipid profile – cholesterol, LDL, HDL 
  • Proteins, albumin, alkaline phosphatase, ALT, AST, bilirubin
  • Blood urea nitrogen (BUN), urea, creatinine
  • Inorganic phosphorus
  • Uric acid
  • Calcium

Advantages of autoanalyzer :

  • Hundreds of samples can be analyzed in a very short time by one operating technician.
  • Modern autoanalyzers are tested for multiple analytes simultaneously in the samples.
  • Save time.
  • Small quantity of samples is required.
  • Conserve reagents and materials.
  • Minimize errors and improve productivity.
  • Most suitable for laboratories handling a large number of samples daily.

Disadvantages of autoanalyzers :

  • The cost of the instrument is high, so not suitable for small or medium sized laboratories handling a limited number of samples.
  • It prevents the observer to note any peculiar reaction occurring at any stage of the analysis, which is not uncommon in pathological samples.
  • Skilled persons are required to operate the machine.
  • New generations of machines are coming up every year, so replacement of old ones is necessary, which is not cost effective.

Ans: Please see Jan-2020 (Q-1-c).

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