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Laboratory Technique – January 2018

2nd Year Final Examination of Diploma in Medical Technology Course : January-2018

Group : Laboratory Medicine

Subject: Laboratory Technique (Paper-I)

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


Apparatus and Materials needed:

  • Disposable gloves
  • Sterile, disposable 10 ml syringe
  • 10 ml test tubes, or vials, with or without anticoagulant
  • Sterile gauze pieces moist with 70% alcohol/methylated spirit.
  • Tourniquet


  1. Seat the patient in a comfortable position on a chair with the arm properly supported. The patient, if needed, may be down on a bed.
  2. Apply a tourniquet above the elbow joint.
  3. Ask the patient to open and close his / her fist alternately for some time to make the veins engorged (filled) with blood. The subject is asked to close the fist.
  4. Locate a suitable vein by palpating.
  5. Sterilize the skin over the selected vein by swabbing with the cotton soaked with antiseptic. Allow to dry.
  6. Grasp the back of the forearm and make the overlying skin slightly tight to fix the selected vein.
  7. Hold the syringe in such a way that the shaft remains parallel to the course of the vein.
  8. Prick the skin first and advance about 1 can in the subcutaneous tissue and then pierce the wall of the vein when the blood will automatically fill the syringe.
  9. Open up the tourniquet.
  10. Draw the piston slowly (not faster than the rate of flow of blood).
  11. Open the fist of the patient and withdraw the needle quickly and at the same time press a fresh swab soaked with antiseptic over the skin puncture. And ask the patient to flex the arm and keep it so till the bleeding stops.

Please also see Jan-2020 (Q-4-c).

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


Use of Autoclave:

  • Reusable syringes, needles, lancets, glassware (specimen containers like tubes, petri dishes), Pasteur pipettes, and other articles of equipment and laboratory ware.
  • Culture media and swabs for use in microbiology work. Most agar and liquid culture media can be . 
  • Decontaminating specimens and other infectious waste prior to disposal.

Use of hot air oven:

  • Sterilization of glassware, such as all glass syringes, test tubes, petri dishes, pipettes, flasks, and instruments like forceps, scalpels, scissors, knives, etc.
  • Sterilization of powders, fats, oils, and greases which are impermeable to moist heat.
  • Sterilization of cotton swabs.

Use of Incubator:

  • Growing microorganisms on various culture media. 
  • Determination of enzymes in the specimen by end point reaction methods.
  • Determination of glucose, urea, uric acid, cholesterol, triglyceride etc. by enzymatic methods.

Use of water bath:

The water bath is used to carry out various chemical reactions at specific temperatures, depending upon the requirement of an experiment.

The various uses of a water bath are listed below:

                            Use                      Temperature
Determination of serum enzymes37°C
Enzymatic determination of glucose, urea, cholesterol, triglycerides etc.37°C
Serological determinations56°C
Determination of triglycerides by acetyl acetone method70°C

Uses/Clinical Importance of Colorimeter: 

Colorimeter is a common instrument used in the clinical chemistry laboratory for the estimation of the concentration of substances present in a patient’s sample, such as-

  • Plasma glucose
  • Blood urea
  • Serum creatinine
  • Serum bilirubin
  • Serum albumin
  • Aspartate aminotransferase (AST)
  • Alanine aminotransferase (ALT),
  • Lipid profile (Total Cholesterol, HDL, TG, LDL)
  •  Serum amylase

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

Workflow Principle of Colorimeter


A flammable chemical is one that readily ignites (catches alight) and burns.

Flammable chemicals:

  • Extremely flammable, eg, acetone, diethyl ether etc.
  • Highly flammable, e.g., absolute ethanol and methanol, 70% and above ethanol and methanol, methylated spirit, isopropanol (isopropyl alcohol), toluene, alcoholic reagents and indicators etc.
  • Flammable, e.g., glacial acetic acid, acetic anhydride, xylene etc.

Safe storage and use of flammable chemicals:


  • Only small quantities (not over 500 ml) of flammable chemicals and reagents are kept on laboratory benches and shelves.
  • They are stored in a closed steel or thick plywood box at ground level, preferably in an outside locked store which is cool and well ventilated.
  • Flammable and oxidizing chemicals should not be stored together.

Safe use:

  • The laboratory is kept well ventilated to prevent any build up of flammable gasses and vapours. 
  • Before opening a bottle containing a flammable liquid, it is to be sure that there is no open flame within 2 metres such as that from a Bunsen burner, spirit lamp, kerosene or gas burner. The distance is 3 meters in using ether or acetone.
  • Not to light a match or use a lighted taper near to a flammable chemical.
  • No one is allowed to smoke in or adjacent to the laboratory.
  • Dispensing containers of flammable chemicals should be placed well away from the rack used to heat stain on slides in the Ziehl-Neelsen technique. Trays are used to hold the containers.
  • A water bath is used to heat a flammable liquid. Not to heat directly on a hotplate or over an open flame. Not to flame the neck of a bottle or tube containing a flammable substance.


Optical principles of a microscope:

1. Magnification:

To see clearly and distinctly the structures (say in a cell), their image must be magnified many times.This is attained by both the lenses of eyepiece and objective.

The total magnification of the object is the multiplication value of the magnifying powers of the

eyepiece and the objective. Thus, with 10X, 40X and 100x magnification of the eyepiece, the magnifications of the three objectives will be:

  • Low power objective (10X) 10X10 – 100 times 
  • High power objective (40X)=40X10-400 times
  • Oil immersion objective (100X)= 100X10-1000 times.

2. Resolution (Resolving power):

It is the ability of the microscope to show closely located structures as separate and distinct from each other. 

The resolution power of a microscope depends on the wave-length of the light and numerical aperture (NA) of the objective lens. As the NA increases, the resolving power of the microscope increases. 

The resolution power of a microscope is expressed in terms of limit of resolution (LR). The formula for determining LR is:

LR= 0.61 X W 


where. W = wavelength of light rays, and NA = the numerical aperture of the objective.

3. Definition:

It is the power to make the outline of the object clear and well-defined by eliminating the chromatic aberration and spherical aberration. 

Manufacturers of objectives correct the chromatic and spherical aberrations by combining lenses of different dispersive powers.

Please also see Jan-2020 (Q-2-e).


Immediate treatment of bleeding (or haemorrhage) / First aid of Haemorrhage:

1. Pressure and packing to stop bleeding: External bleeding can usually be suppressed by applying pressure. This can be done by –

  • Direct pressure with sterile bandage, hand may be used to put more pressure on the wound over the bandage when needed.
  • A clean pressure dressing.
  • Digital pressure, e.g., the use of finger and thumb.
  • Tourniquet (if necessary).
  • Packing (in nasal bleeding).

2. If the pressure points are known at appropriate points, pressure is applied on them firmly for 10-15 minutes.

3. Elevation of the injured part (if no bone fracture is suspected).

4. If the bleeding continues, more pads are added, not removing the original dressing.

5. Rest: The victim is placed in a comfortable position.

6) The victim is shifted to a hospital as soon as possible for –

  • Treatment of shock
  • Restoration of blood volume
  • Specific treatment according to the cause of bleeding.

Management of internal bleeding:

1. Securing and maintaining an open airway. 

2. The victim is kept with the head low, the legs are raised using pillows.

3. Body heat is maintained using blankets, or other clothing. 

4. The victim should never be given anything by mouth. 

5. The victim is shifted to a hospital as quickly and safely as possible.

Please also see Jan-2019 (Q-4-e) and Jan-2021 (Q-4-c).

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

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

Ans: Please see Jan-2019 (Q-1-c).

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

Ans: Please see Jan-2019 (Q-1-d).


Laboratory report:

Laboratory report is the documented outcome of a test result, which contains particulars of the patient, name of the test and findings of the test with necessary films, photographs etc.

Delivery of report:

After performing a test in the laboratory the patient is asked to collect the test report from the delivery desk at or after a due time. The report is delivered in a hard copy, printed on specified form. This is known as delivery of report.

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


A. General jobs:

1. Laboratory safety:

a) Safety of the laboratory staff-

  • Medical technologists and other laboratory staff should be properly immunized.
  • Should wear proper and protective dress and remain alert about personal protection.
  • Should collect and label the high-risk specimens and samples properly. 

b) Safety of the patient-

  • Should maintain safety measures in every individual procedure.
  • Should keep the arrangement of First Aid for emergency situations and complications.

c) Safety of equipments and instruments –

  • Should ensure cleanliness and maintain the laboratory room, equipment, apparatus and glasswares according to manuals and instructions by subordinate staff.

d) Arrangements and security of the laboratory-

  • Should ensure proper setting up of furniture, equipment and instruments.
  • Should supervise and maintain the laboratory rooms.
  • Should ensure appropriate security measures by laboratory staff.

2. Commitment to be patient: 

a) Should be well behaved to the patients and attendants.

b) Should explain procedures and consequences of laboratory tests to the patients and their attendants.

c) Motivation and counseling of the patients where needed.

d) Taking consent of the patients and attendants where needed.

3) Handling of poisonous and infected materials:

a) Proper labeling and storage of infected and poisonous materials.

b) Proper handling of the reagents and chemicals as per instructions.

4. Updating and innovation of laboratory facilities continuously 

5. Responsible for inter-departmental coordination and cooperation.

6. Should arrange safe disposal of used and infected waste materials. 

7.Responsible for quality control in all aspects of laboratory activities.

8. Should prepare indents, collect logistics, and maintain ledger / register and should report. 

9. Supervision and training of junior colleagues.

B. Specific jobs:

1. Job description at Primary health care level. 

II. Job description at Secondary health care level.

 III. Job description at Tertiary health care level.

IV. Job description at Teaching institutes.


Reception and preparation of the patients coming for investigations in the laboratory:

The steps of reception of the patient include:

  1. To receive the patient cordially.
  2. To look at the prescription / advice slip for the advice of the consulting physician regarding the test
  3. To register the patient with ID number, personal particulars, name of the investigation etc.
  4. To request the patient to wait if required.
  5. To prepare the patient according to the nature of the test. The patient is asked to follow the advice to get a correct result.
  6. To explain the patient for special preparation in case of selected tests, such as-
  • Glucose tolerance test 
  • C/S of urine, stool 
  • Test for throat swab
  • Semen analysis


Procedure of stool collection:

  • For clinical purposes, a fresh stool specimen, uncontaminated with urine, is collected into a suitable sized, clean, dry, leak-proof, wide-mouthed jar with a screw cap. 
  • The container need not be sterile but must be free from all traces of antiseptics and disinfectants.
  • A large teaspoon amount of stool is adequate or about 10 ml of a fluid specimen. If mucus and blood are present, they should be included in part of the specimen to be examined. 
  • Several specimens collected in alternate days may be required to detect parasites that are excreted intermittently, e.g. Giardia.
  • For occult blood testing, it is usual to collect three specimens on different days. 
  • After collection, the specimen container should be labeled indicating the name of the patient, identification number, date and time of specimen collection and the test required.
  • Stool specimen should not be left uncovered. It is necessary to prevent the drying effect.
  • Stool specimen should be examined within 1 hour of collection. 

Safe disposal of stool:

1. If disposable containers for stool are used, the specimens are disposed by incineration, i.e. destruction by burning both of the contaminated disposables and specimens. 

2. Alternative way of disposal of stool:

  • The remaining stool specimen is dumped in the soil and covered with a layer of soil or brick. 
  • The empty stool container is washed with running water and is kept in 5% phenol for 24 hours.
  • The container is then washed with soap water or detergent powder mixed water.
  • Then, the container is washed with tape water and is sterilized in a hot air oven or autoclave.

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

Ans: Please see Jan-2021 (Q-4-d).


The modern clinical laboratory is a workplace where many hazardous chemicals, complex instruments, and potential pathogens are encountered on a daily basis. The laboratory can be a safe place to work and learn if possible risks and hazards are assessed and a safety code is followed.

Types of safety code:

  1. Laboratory dress code and Personal Protective Equipment (PPE)
  2. Practice of good personal habits
  3. Good laboratory techniques
  4. Safe work environment
  5. Safe work practices
  6. Emergency first aid
  7. Preparing for and responding to emergencies/fire
  8. Reporting an accident or laboratory related illness

Here is a short note on the most important safety codes in lab technique:

  • Dress appropriately: Wear a lab coat, safety goggles, and closed-toe shoes. Long hair should be tied back.
  • Be aware of your surroundings: Know the location of fire extinguishers, eyewash stations, and emergency exits.
  • Read and understand the lab procedures before you begin: If you have any questions, ask your instructor.
  • Handle chemicals with care: Wear appropriate personal protective equipment (PPE) when handling chemicals, such as gloves, goggles, and a respirator.
  • Label all containers clearly: This includes the name of the chemical, its concentration, and any hazards associated with it.
  • Dispose of waste properly: Follow the specific instructions for disposing of chemicals and other hazardous materials.
  • Do not pipette by mouth: Use a pipetting device instead.
  • Do not eat, drink, or smoke in the lab.
  • Keep food and drinks out of the lab.
  • Wash your hands thoroughly after handling chemicals or lab equipment.
  • Clean up spills immediately.
  • Report all accidents and injuries to your instructor immediately

Ans: Please see Jan-2019 (Q-5-b).

Ans: Please see Jan-2021 (Q-5-c).

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

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