Bank Of Questions | Clinical Laboratory | CMT NTA 4

Bank Of Questions | Clinical Laboratory | CMT NTA 4

 1. The following solution is used for washing hands before walking out of the laboratory

A. 20 of dilution with Lysol

B. 2 Lysol

C. 10 antiseptic

D. 5 Lysol

E. 20 Lysol

2. Micro-organisms responsible for laboratory infections in respiratory tract

A. Proteus

B. Anaerobes

C. Haemophilus influenza

D. Salmonella species

E. Klebsiella species

3. Physical method of sterilization include the followings EXCEPT

A. Sterilization by irradiation

B. 50 glycerol solution

C. Sterilization by filtration

D. Most heat sterilization

E. Dry heat sterilization

  4 .The following temperature is used for pasterilization

A. 62 for 30 minutes

B. 100 for 15minutes

C. 73 for 15 minutes

D. 63 for 15-20 seconds

E. 63 for 30 minutes





 5. Major Equipment used in the laboratory includes the followings EXCEPT:-

A. Haemocytometer

B. Water filter

C. PH meter

D. Colorimeter

E. None of the above

6. The important parts of a microscope include one of the followings:-

A. arm

B. base

C. objectives lenses

D. lamp rheostat

E. foot

7. All wet preparation specimen in a laboratory are observed by using:-

A. Microscopy

B. Dark gland illumination microscope

C. Oil immersion objectives

D. Low power and high power

E. Magnification objectives by eye’s

8. Safety precaution takes when you collect blood sample from patients include the followings EXCEPT:-

A. Discard all used terms in a dustbin

B. Keep work area organized clean and disinfect

C. Put a new gloves before collecting blood

D. If  blood is spilled, mop and disinfect area immediately

E. Consider every person as potentially infectious and susceptible to infection




9. A macroscopic examination reports the physical appearance of specimen, this includes a description of the followings EXCEPT:-

A. colour

B. consistency of stool

C. visible contents

D. white blood cells seen

E. normal stool


10. Which of the followings is not a procedure for collecting Midstream urine:

A. Wash genital area

B. Begin to urinate without collecting urine

C. After a few ml have passed, collect in container 10-20 mls if possible

D. Instruct the patient to collect about 20mls of urine directly into a clean container

E. Finish urinating without collecting

11 Carcinogens are those chemicals that can cause cancer when ingested, inhaled, or come in contact with skin, here below is an example of those chemicals excluding one which is corrosive when contact the skin. Help me on identification of corrosive chemical from a group of carcinogenic chemicals

F. Benzidine

G. Nitrosamines

H. Nitrosophenols

I. O-dianosidine

J. Trichloroacetic acid

12 During macroscopic analysis of stool, A normal stool for adult should be:

F. Black with mucus

G. Black without mucus

H. Soft Brown

I. Watery brown

J. Colorless



13 While performing glucose testing in urine, the following reagent is used

A. salphosalicylic acid

B. acetic acid

C. Benedict solution

D. Etheline diamine tetra-acetic acid

E. Glucose-6-phosphate

14. The science of detecting antigens(bacteria,viral or parasites)or antibodies to antigens in blood, serum or plasma is termed as:

a. serological technique

b. microscopic technique

c. haematological technique

d. cultural technique

e. biochemical technique


15. The system of the microscope which consists of objectives lenses are:-

a. Adjustment system

b. Illumination system

c. Mechanical stage system

d. Magnification system

e. Iris diaphragm system

16. The cyst of amoeba are easily seen by the aid of:-

a. Adding the cover glass on the smear with saline

b. Gentian violet to make easily to see the parasite’s

c. Physiological saline then emulsify with applicator

d. Cadal wood oil on the smear to see the amoebae

e. Adding 1 drop of Iodine on the slide





17 The following parasite ova is characterized by lateral spine on microscopic observation:-

a. AscaiesLumbricidrs ova

b. TrichuraTrichiura ova

c. Adult tape worm

d. Sch. Haematobium ova

e. Sch.mansoni ova

18 The storage of blood prior to transfusion must be at the temperature of:-

a. 5oC – 9oC

b. 7oC – 8oC

c. 4oC – 6oC

d. 30C – 10oC

e. 12oC – 13oC

19 The best result are obtained using Giemsa staining with buffer solution at:-

a. Ph 6.0

b. Ph. 7.8

c. Ph. 8.4

d. Ph. 7.2

e. Ph. 9.2

20 Acid fast MEANS:

A. Microorganism that are fast stained in the laboratory by Z-N stain

B. Microorganisms that are not resistant to decolorization with acid during the staining process

C. Microorganisms that are resistant to decolorization with acid during the staining process

D Microorganisms that are resistant to decolorization with alkaline during the staining process 


21 Which is the sensitive reagent for protein test in urine?

A. 5% acetic acid

B. 20% acetic acid

C. 2% acetic acid

D. 25% acetic acid

E. 70% acetic acid

22 One of the following is the probable value for the adult random of blood glucose.

A. 3.3-7.4mmol/l

B. 1.1-4.4 mmol/l

C. 3.6-6.4 mmol/l

D. 2.4-5.3 mmol/l

E. 2.2-3.4 mmol/l

23 The percentage of the patient being free of disease, as the test negative is termed as:-

A. Qualitative

B. Predictive value

C. Sensitivity

D. Specificity

E. Quantitative

24  Wet blood films are examined microscopically under the following objectives

A. 10X followed by 40X

B. 40X followed by 10X

C. 10X followed by 100X

D. 100X followed by 40X

E. 100X followed by 10X

25 Which of the following blood group has the highest percentage?


B. A

C. O

D. D

E. B


26 Black water fever is a condition associated with one of the plasmodium species

A. Plasmodium malariae

B. Plasmodium vivax

C. Plasmodium ovale

D. Plasmodium falciparum

E. Plasmodium ova

27 Which one is NOT a morphological feature of Mycobacterium Tuberculosis?

A. Non motile

B. Capsulated

C. Rod shaped

D. Non spore forming

E. Waxy material



28  One of the following is not a type of urine specimen

A.  First morning

B.  Random urine  

C.  Terminal

D.  Midstream

E.  Fasting

29. One of the following is used as a counter stain in gram staining technique

A. 10% Acetone

B. Dilute carbolfuchsin

C. Lugol’s iodine

D. Malachite green

E. Gentian violet

30 In the ZN staining method, Carbolfuchsin is combined with one of the following reagents to penetrate the mycolic acid in the mycobacterial cell.

A. Phenol

B. Malachite green

C. 10% acetone

D. 1% methlene blue

E. 20% sulphuric acid

31   . All wet preparation specimen in a laboratory are observed by using.

a. Low power and high power

b. Oil immersion objective

c. Dark gland illumination microscope

d. Magnification objectives by eye’s

e. Macroscopically


32 The following solution is used for washing hands before walking out of the


a. Antiseptic 10%

b. 2% Lysol

c. Disinfectant 50%

d. 5% Lysol

e. 20% of dilution with Lysol


33 Which of the following is the cestoda parasite:-

a. Balantdium colli & Entamoeba Histolytica

b. Trypanasdoma & microfilatria

c. Hookworm ova & Ascaries ova

d. Taenia saginata & Hymenolepis nana

e. Cryptosporidium and schistosoma

34 All of the following bacteria are gram negative EXCEPT:-

a. Escherichia colli

b. Salmonella typhi

c. Shiggella  spp

d. Proteus spp

e. Ricketisia tsutsugamushi


35 The following worm is seen in blood circulation, during night time (Noctunal)

a. Onchercerrca volvulus

b. Loa loa

c. Wucheria bancrofti

d. Brugia malayi

e. By skin smear


36 An individual test for HIV rapid test, only one line appeared on the test line . which of the following will be the best interpretation of this result

a. The individual result is HIV positive

b. The individual result is HIV negative

c. The individual result  is HIV

d. The individual result is indeterminate

e. The individual result is not read


37 The following parasites has lateral spine:-

a. Trichomonas  Virginals

b. Schistosoma  Mansoni

c. Schistosoma Japanicum

d. Schistosoma Haemotobium

e. Schistosoma intercalatum


38 The following are gram positive EXCEPT:-

a. Bacilli anthrax

b.  iiClostridium tetani

c. Helicobacter pylori

d. Mycobacteria diptheria

e. Candida albicans


39  External quality assessment (EQA) schemes involve the distribution of small panels of samples with known results to all testing sites is

a. On site evaluation

b. External audit

c. Internal audit

d. Proficiency test

e. Quality control program


40 Cysts of amoeba are easily seen by the addition of

a. A drop of normal saline on the smear

b. X10 objective & X 40 objective are used in more conformation

c. Simple stain by wet preparation

d. Iodine stained

e. Eosin stained 






























1. Regarding the  parasites and bacteria in urine :

A. TRUE………… schistosoma haematobium

B. TRUE……… trichomonas vaginalis trophozoites

C. FALSE…… schistosoma mansoni

D. FALSE…… Giadia lamblia

E. FALSE……… Eterobius vamicularis

2. The normal PH of urine is slightly acidic

A. FALSE…………  5.5-6.6

B. FALSE…………  5.4-6.0

C. FALSE………  5.6-6.5

D. FALSE…………  5.0-6.0

E. TRUE…………  5.5-6.5

3. Regarding a number of specimens are collected by swabs include;

A. TRUE……vaginal discharge

B. FALSE… midstream urine

C. TRUE… rectal swab

D. FALSE……sport collection sputum

E. TRUE… pus discharge from different body site

4. Regarding the collection of rectal swab:

A. TRUE……prepare the patient

B. FALSE… take wet sterile swab

C. FALSE…… insert five inch into the anus

D. TRUE… put into a transport media

            E  FALSE send to the laboratory for sterilization

5.  Regarding the thick blood smear, the following parasites can be observed:

a. TRUE Plasmodium species

b. TRUE Borellia

c. FALSE Treponema pallidum

d. TRUE Trypanosomes

e. TRUE Microfilariae






6. The Serum means

a. FALSE  Fluid that separates clotted blood

b. FALSE  Fluid that separates un clotted blood

c. TRUE  Fluid that separated from clotted blood

d. FALSE  Fluid that separated from plasma

e. TRUE  Fluid that separated from coagulated blood

7. Concerning materials, reagents and equipments used during blood smear for parasites

a. FALSE coverslip

b. TRUE Field/Giemsa stain

c. FALSE Crystal violet/gentian violet

d. TRUE Microscope

e. TRUE staining rack/staining jar


8. Regarding blood group of an individual:

a. TRUE blood group A has A Antigens and B antibodies

b. TRUE blood group O has no antigens

c. FALSE blood group AB has no antigens

d. FALSE blood group O has no antibodies

e.  TRUE blood group AB has no antibodies 


9. Concerning Laboratory Microscopy Technique

a. Serological techniques…TRUE

b. Biochemical techniques…TRUE

c. Widal test technique…FALSE

d. Fomal ether concentration technique…FALSE

e. Gram stain technique……… TRUE


10. Regarding a thick blood smear is used to detect the following parasites

A.  Borrelia…TRUE

B. Yessinia…FALSE

C. Typanasomes…………TRUE

D. Plasmodium species   ……TRUE

E. Protozoa………FALSE






11. With regard to Sop’s for collection of pus:-

A. Label the specimen container after collection…… FALSE  

B. Label the specimen container bearing hospital number….TRUE  

C. The specimen should not reach the laboratory after collection…..FALSE   

D. Spot specimen is collected after the analysis of morning specimen …FALSE.

E. Specimen collection container should be wide mouthed and capped …TRUE.


12. Concerning swab specimen’s collection.

A. Cerebral spinal fluid (CSF)…..FALSE

B. High vaginal swab (HVS)….TRUE

C. PUS specimen ….TRUE

D. Throat discharge….TRUE

E. Sputum ….FALSE


13. ABO grouping:-

a. FALSE ………Anti sera are not needed to perform ABO group

b. TRUE ………There are two common method used to perform group

c. TRUE ……….X match patient serum and cells suspension from the donor’s

d. TRUE ……Microscope is used to read the compatibility

e. FALSE ………There are three type of ABO GROUP

14. Sugar in blood:-

a. FALSE ………Benedict solution is the reagent used

b. FALSE ………The blood are mixed with sodium hydroxide

c. TRUE ………Glucoplus  is the common method used

d. FALSE ……Citrate phosphate Dextrose is the one of the reagent

e. TRUE ………Fast blood examination are Important


15. . Protein in urine:-

a. TRUE………The most important found is the albumen

b. TRUE………Are coagulated by heat if is present

c. FALSE ………10% acetic acid can be used in estimation

d. FALSE…………Is very difficult to be detected

e. FALSE………Can be caused by congestive failure


16. . Compatibility test

a. TRUE………Microscope is used to see the cells

b. TRUE………Donors cells are tested with patient  serum

c. FALSE………10% of cells suspension of donor is important

d. FALSE……….If the cells remain clear the result is incompatible

e. FALSE………Donor serum and antisera are mixed together





Match laboratory diagnostic test in column A against clinical condition/disease in column B


Laboratory diagnostic test(COLUMN A)


Clinical condition/disease(COLUMN B)


……H….steam under pressure


Used to examine viruses


……c….wound and skin infection


Examination of bacteria and fungi


…...…A..electron microscope


Presence of pathogenic fungi in tissue


………E .sepsis


When taking venous blood sample


….…D….applying toniquet


Presence of pathogenic bacteria in the tissue








When taking capillary







Match macroscopic findings of urine in column A against possible cause in column B










……A…Red and Cloudy




……C…Brown and cloudy


Black water fever




Urinary tract infection


….…G…..Milky white


Certain poison e.g. phenol




Liver disease




Bancroftian Filariasis




Enteric fever



Match laboratory diagnostic test in column A against clinical condition/disease in column B


Laboratory diagnostic test(COLUMN A)


Clinical condition/disease(COLUMN B)


……E….Benedict’s qualitative test




……C….DNA PCR test




…...A…..Rapid plasma regain


Genital chlamydial infection


……G….Widal test


Urinary tract infection


….…F….Whiff test


Diabetes mellitus




Bacterial vaginosis




Typhoid fever




Anaemia in pregnancy



Match macroscopic findings of urine in column A against possible cause in column B










…A……Red and Cloudy




…C……Brown and cloudy


Black water fever




Urinary tract infection


….G……..Milky white


Certain poison e.g. phenol




Liver disease




Bancroftian Filariasis




Enteric fever




Match the Hemoglobin (Hb) values in column A against their corresponding factors in column B.



1.  Adult male       (  F  )

 A.  140g/l

2.  Adult woman   (  E   )

 B.   155g/l     

3.  Children aged 6-12 years ( B   )

 C.  110-140g/l

4.  Newborn (  A   )

 D.  100g/l

    5.   Children aged 2-5 years (  C   )

 E.  120g/l


 F.    130g/l


 G.    7.5g/dl


 H.     25g/dl



2. Match the reagents used in Gram stain in column A against their possible role during gram staining technique in column B.



1.  10% acetone …          ( B  )

 A.  Can be used in place of  Lugol’s iodine

2.  Gentian violet             ( E  )

 B.   Decolouriser     

3.  Dilute carbolfuchsin   ( F  )

 C.  Can be used in place of Carbolfuchsin

4.  Lugol’s iodine            ( G  )

 D.  Accentuator

    5.   Neutral Red/ Safranin ( C  )

 E. Primary Stain


F. Counter Stain


G. Mordant


H.  90% Alcohol



1. Matching item of column A parasite or bacteria and column B diagnostic procedures




i. O…no AFB found in100 fields

ii. C…AFB 10 AFB per field

iii. E…AFB 1-10 found AFB found in 100 field

iv. D…AFB 1-10 AFB per field

v. G....AFB 1-10 per 10field



A. 3+

B. 0

C. Record exact number

D. ++

E. 1+

F. 4+

G. +++

H.  2+




2. Matching item of column A stain reagent and column B fuction to a corresponding reagent




i. F.......... hyperglycemia

ii. .E.........lovibond method

iii. .D......... tall Quist method

iv. .A........... colorimetric method

v. .C........... fasting blood glucose

A. Haemoglobin cyanide

B. Glucose estimation

C. Blood collected before taking meals

D. Methods is a booklets

E. Disc to matches colour

F. sweating

G. increased thirst

H. Gram stain







1. Mention five standard safety precaution when drawing blood; `

A. Consider every person (patient or staff) as potentially infectious and susceptible to



A. Wash hands before and after taking a sample from each patient


B. Put on new gloves before collecting blood


C. If blood is spilled, mop and disinfect area immediately


D. Keep work area organized, clean, and disinfected


E. Discard all used items in appropriate containers


2. List five proper handling of specimen

a. A Specimens must be properly handled from point of collection to delivery in the        laboratory

b. Results of laboratory investigations are only as good as the sample received by the Laboratory.

c.  Use appropriate collection containers for specific testing needs

d.  Store specimens upright, in racks at the appropriate temperature

e. Note the time of taking the specimens to ensure processing in the correct timeframe

3. Mention five macroscopic appearance of urine

A.  cloudy

B.  red and cloudy

C. brown and cloudy

D. silvery shine or milk

E .black…

F .yellow/green/brown


4. Mention five precaution during collection of sputum specimen

a.  Patient who is coughing is of a greater danger to staff than the specimen.


b.  When collecting and receiving the specimen be sure to adhere to infection prevention and Control standards.

c. Do not collect sputum in the laboratory or clinic room

d.  Do not stand in front of the patient during specimen collection


e.  Use appropriate leak proof containers with a wide mouth

f. Label a clean sputum container (on the side and on the lid/cover) before obtaining

a. Specimen

g.  Collect specimen in a well-ventilated area, preferably outdoors in the sunlight

h.  Ensure that no one stands in front of the patient while producing sputum

i.  Ensure container is labeled and closed firmly with lid after the specimen is collected

j.  Wash your hands with antiseptic after collecting specimen

5. List five number of specimens which are collected by swab;

a. Conjunctiva discharge


b.  Urethral discharge


c. Vaginal discharge


d.  Rectal swab


e. Pus discharge from different body sites

6. Mention five cellular elements found in urine

a. White blood cells (WBC) (pus cells)


b. Red blood cells (RBC)


c. Epithelial cells


d. Yeast cells


e. Bacteria


f. Trichomonas vaginalis trophozoites


g. Helminthic ova (S. haematobium


7. List two types of urine samples

              A…For routine examination urine is collected in a clean leak-proof container.


              B…. For culture purposes midstream urine is collected in a sterile leak proof container


8. Mention five ova of parasites found in stool

a. Hookworms


b. A.lumbricoides


c. T.Trichuris


d.  E.vermicularis


a. T. saginta


b. T. solium


c.  H. nana

9. List five advantages of HIV rapid testing

A. Patients receive results in under 30 minutes

B. Whole blood can be used (finger prick)

C. Minimal skill and equipment required for accurate interpretation

D. Tests are easy to use and read

E. Most test kits can be stored at temperatures between 2-30oC

F. Small numbers of patients can be tested at once (unlike ELISA, which requires a batch of samples)






10. Before performing the HIV test the tester should record/indicate/have the following information, List five of them

A. The test date

B. Client identification

C. Name of the person performing the test

D. The name of the test

E. The expiration date of the test kit

F. Test lot and batch number of the test kit

G. A standard operating procedure

H. Results slip and register

11. Serological Techniques is the science of detecting antigens (bacterial, viral, parasitic) or antibodies to antigens in blood or serum. Mention five examples of those serological tests that are commonly performed in the laboratory.

A. Malaria Rapid Diagnostic Test (mRDT)

B. HIV rapid test


D. VDRL test

E. Widal test


12. A microscope is a piece of optic equipment that aids in the visualization of invisible objects that would otherwise be invisible to the ‘naked eye.’ Mention five types of microscopes that are used in the laboratory.

A. Ordinary Light Microscope

B. Phase Contrast Microscope

C. Electron Microscope

D. Fluorescence Microscope

E. Dark Field Microscope

13. Before collection of blood specimens, person should gather all necessary material for the procedure, list six(6) essential materials for the collection of venous blood.

A. Specimen containers

B. Tourniquet

C. Needles and syringes

D. Small bore needles

E. Gloves

F. Aprons or laboratory coats

G. Alcohol swabs

H. Cotton Gauze/Wool

I. Hand towels (Preferably disposable)

J. Waste disposal containers

14. Mention five parasites that can be demonstrated through stool wet preparation

A. ascaris lumbricoides

B. hookworm

C. strongloides stercolaris

D. taenia species

E. trichuris trichiura

15. List five specimens that can easily collected using swabs stick.

A. Conjunctiva discharge

B. Urethral discharge

C. Vaginal discharge

D. Rectal swab

E. Pus discharge from different body sites


16. Outline four categories of gram stain reagents with one example to each category

A. Primary Stain- Methyl violet or gentian violet or crystal violet

B. Mordant- Lugol’s iodine

C. Decolouriser-10% Acetone/Alcohol

                  D  Counter Stain- Dilute carbolfuchsin or sufranin or neutral red


17. Dark ground Illumination is used to examine.

A. Treponema pallidum

B. Borrelia species in blood

C. Leptospirae in urine

D. Microfilaria in blood

E. Vibrio cholerae


18. Name five advantages of HIV Rapid Test.

A.  Patients receives results under 30 minutes

B. Whole blood can be used(finger prick)

C. Minimal skills and equipments required for accurate interpretation

D. Tests are easy to use and read

E. Tests can be tested at once unlike ELISA which requires a bunch of samples


19. Wet preparation techniques allow observation of the following.  

A.  Red blood cells, pus cells and macophages

B. Motile trophozoites of protozoa

C. Bacteria with characteristic shape and motility

D. Cysts of protozoa

E. Helminthes ova

F. Helminth larvae.


20. Pin point five example of serological tests.

A.  Malaria rapid diagnostic tests mRDT

B. HIV rapid test

C. RPR test

D. VDRL test

E. Widal test




21. State five major symptoms of hyperglycemia.

A.  Increased thirsty

B. Increased urination

C. Fatigue

D. Blurred vision

E. Slow wound healing


22. List five important information before performing the test.

A.  The test date

B. Client identification

C. Name of the person performing the test

D. Name of the test

E. Expiration date

F. Test lot and batch number of the test kit

G. Result slip and register


23. Mention five biochemical tests.

A.  Liver transaminase tests

       B. Test for metabolic product such as creatine

       C.  DNA/RNA detection

       D.  Protein in urine

24.  To investigate anemia a number of hematological tests are performed including……. ( 5 marks)

A. Haemoglobin estimation

B. Blood film for malaria

C .White blood cells total count and differential count

D .Red blood cells morphology

E .Sickling test




25. Mention 5 steps procedure (SD Bioline HIV Rapid test) 

1. Serum, plasma or whole blood is used

2. Pipette required amount of specimen and add to the device well (10μl for serum or

3. .plasma, 20μl for whole blood)

4.  Add three drops of essay diluent

5. .Wait for 1to 20 minutes

6. Read the results


       26. Outline five advantages of HIV Rapid Test

1. Patient receive results in under 30 minutes

2. Whole blood can be used (finger prick)

3. Minimal skill and equipment required for accurate interpretation

4. Tests are easy to use and read

5. Most test kits can be stored at temperatures between 2-30oC

6. Small numbers of patients can be tested at once (unlike ELISA, which requires a batch of samples  


26. Write five parasite that can be diagnosed  in a thin blood film

1. Malaria parasite

2. Borellia

3. Trypanosome

4. Leishmania

5.  Leptospires


27. a) Mention three antibody methods to detect HIV in human

1. human immune deficiency  virus (HIV) Rapid tests

2. Enzyme Linked Immunosorbent Assay (ELISA)

3. Western Blot (confirmatory test if available 

     b) Mention two HIV Rapid Tests Used (Currently) in Tanzania

1. SD Bioline HIV-1/2

2. Unigold HIV




28. . Write five common tests that used to investigate anemia

1. Haemoglobin estimation

2. Blood film for malaria

3. White blood cell total count and differential count

4. Red cell morphology

5. Sickling test


         29. A) Mention three false positive result for ABO grouping

1. Roulex formation  

2. Infected red blood cells

3. Agglutination by cold agglutinin


       b). Mention two False negative result for ABO grouping   

1. Faire to react due to important antisera

2. Use of heamolysed blood  


      30. Stain by dipping the slide, keeping it steady, into the jars as follows:

1. Fields stain A four seconds (four dips)

2. Clean water five seconds (five dips)

3. Field stain ‘B’ four seconds (four dips)

4.  Clean water five seconds (five dips)

5.  Drip dry


      31 . Mention five Laboratory diagnostic techniques 

1. Microscopy techniques 

2. Romanowsky staining techniques

3.  Serological techniques

4.  Biochemical techniques

5.  Cultural techniques

















1. A man aged 35 years old presented to the health centre complaining of varying amount of urethral discharge most evident in the morning also difficulty in maturation. A doctor in charge order urethral swab for gram stain. Describe a gram stain


            Gram stain is a differential stain which differentiates organisms into two groups namely gram positive and gram negative. A gram positive organism retains primary colour and gram negative organism’s picks up counter stain reagent. Gram positive organisms their cell wall contains a large amount of petidoglycan and teichoic acids .Gram negative organisms their cell wall contains only a small amount of petidoglycan

   Main body                                                                                                        

           Material when performing gram stain  include Microscope , Staining rack, Diamond pencil,  Glass slides, Bunsen burner / spirit lamp, Inoculating handle and loop, Disposable gloves, Slide holding forceps, Matches, Immersion oil, Disinfectant                                


            Reagent used  are Primary stain consists one of the following ,Methyl violet or  Crystal violet or  Gentian violet ,Mordant  stain consist  Lugols iodine , Decolourizer consist 10%Acetone in alcohol and Counter stain consists one of the following ,Safranin  or Dilute carbofucshin or Neutral red                                                                                                  



The Procedure for Gram Stain Technique                                                                       

· Prepare a smear, allow to dry and fix with gentle heat

· Apply Primary stain and allow to act for 30 to 60 seconds

· Wash with running water

· Apply mordant stain  and allow act for 30-60 seconds

· Wash with running tape water

· Decolorize until no more colour is coming out

· Wash with running tape water

· Apply one of the following counter stain and maintain time as follows;

Dilute carbofuschin-30 seconds

Safranin or Neutral red 3minutes

• Wash with clean water

• Leave it standing on the draining rack to dry

• Examine slide microscopically using X100 objective lens with immersion oil

• Report findings


2. Amina is 26 years old.  She reports to your Health centre with a history of abdominal pain, diarrhea, general body malaise, vomited and coughing .A doctor in charge order urine specimen and stool for wet examination. Describe microscopic wet preparation for examination stool specimen.


           Microscopic wet preparation is the process of examine a stool sample under microscope. During examination you should have the following material 0.85% physiological saline, glove, mark pen, glass slide, microscope, cover slip, applicator stick and container for west


• Label the slide with patient laboratory number

• Place one or two drops of physiological saline on a clean glass slide

• Take a small sample with a small glass rod or wooden applicator stick and emulsify with the saline on the slide

• Remove debris

• Apply a cover slip

• Place the slide on the microscopic stage

• Swing the x10 objective into position and examine the preparation systematically

• Examine structures in detail using the x40 objective

• Record the findings





3. Explain the principles that underline serological, biochemical and cultural techniques.   



A.  Serological techniques the science of detecting antigens (bacteria, viral, parasitic or antibodies to antigens in blood)

The antigen-antibody reactions results in agglutination, neutralization or haemolysis.

· Principle: when an antigen is exposed to an antibody in suspension in an appropriate concentration they react.

· The reaction can be a visible one, such as the formation of a precipitate made up of a complex antigen and the antibody.

· Serological tests are used in two ways.

· A known antibody can be used to detect and measure an unknown antibody.

· A known antigen can be used to detect an unknown antibody.

· Examples of serological test  mRDT, VDRL, HIV, Widal test


B. Biochemical techniques measure the amount of activity of a particular enzyme or protein or substances in a sample of blood or urine or other tissues from the body.

· Biochemical tests identify the main biologically important chemical compounds in the specimen.

· Examples of biochemical tests, liver transaminase,creatinine

C. Cultural techniques- Microbial culture is a method of multiplying microbial organisms by letting them produce pre-determined culture media under controlled laboratory conditions.

· Pure cultures of single celled organisms usually must be isolated and grown under aseptic conditions, requiring sterilized instruments and filtered or still air.

· Isolated colonies of microorganisms are usually obtained by growth on the surface of a petri-dish

· The petri dish contains an appropriate growth medium for the micro-organism of interest usually  with agar (agar plate)

· To isolate a pure culture, initial sample is manipulated using an inoculation loop or needle to spread and dilute the cells on the surface of the plate.

· The objective is to eventually have some areas of the petri-dish with isolated single cells.

· Use of cultural methods:

· Used to determine the type of organism, its abundance in the sample being tested, or broth.

· Is a primary diagnostic method used as a tool to determine the cause of the infection


4.  Briefly explain on quality control in HIV rapid testing using SD Bioline. (15marks)



 HIV- rapid test is an immune chromatographic test used to detect HIV antibodies in blood.

· Specimens for this technique include whole blood, serum and plasma.

· When performing HIV rapid test three blood samples must be available

· Known HIV Positive sample

· Known HIV Negative sample

· Unknown HIV status sample


   Quality Control in HIV rapid test includes the following:

· Check expiry date of the testing kit.

· Check the integrity of test kit and device

· Document the specimen and patient particulars

· Use SOP

· Follow national HIV testing algorithm

· Report results only when the control band in the test device also present

· Make sure the reading of the result is done within the specified time of the test

· Report and abnormal occurrences  during the procedure

· Make sure positive and negative controls are working before performing the test


CONCLUSION: Students conclusion must reflect to what has been analyzed in regard to the above points.



5. Describe on  how you instruct a patient on proper procedure for spot

Sputum collection

Provide patients with the following instructions for collecting spot sputum specimens:

· Cough sputum in open air (preferably outdoors)

· Inhale deeply two to three times, and breathe out hard each time

· Cover mouth when coughing.

· Cough deeply from the lungs and expectorate sputum

· If possible, observe patient during specimen collection. Stand behind the patient when they are coughing.

· Place the open container close to the mouth and spit the sputum into the container

· Close the sputum container after specimen collection.

· Thank the patient


6. 22 year old lady presents with offensive vaginal discharge for 2 weeks. She has never sought any medical advice since onset of symptoms. Describe the type of specimen required, procedure for collection and investigations that are relevant for this type of specimen



Type of specimen required……High vaginal swab or endocervical swab

It is commonly used to test for the presence of candidiasis infection, bacterial vaginosis and trichomonas vaginalis.

Technique for collection of High Vaginal Swab and Endocervical Swabs

· Procedure

Insert the speculum into the vagina and open fully

Take the sterile swab and pass it high into the posterior fornix of the vagina

Roll the swab for a few seconds to collect the secretions

Replace the swab in the test tube

Label and send the specimen to the laboratory for investigation





· Microscopy

Wet preparation to look for trichomonas vaginalis and candida albicans, bacterial vaginosis (clue cells)

Gram stain for suspected bacterial infection

· Whiff test for suspected bacterial vaginosis

· PCR if chlamydial infection is suspected.

· Culture and sensitivity to identify the causative agent and treatment of choice.

· Pap smear for cervical cytology

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