Lesson 4: Specimen Collection, Handling, and Storage Flashcards
The first step in the laboratory investigation of infectious diseases
Specimen Collection, Handling, and Storage
An improperly collected, handled, and stored sample may lead to ____.
false negative/ positive results
Improper Collection, Handling, and Storage
May lead to false negative/ positive results due to:
-
Contamination due to poor collection technique
- E.g. no aseptic technique before blood collection -
Poor specimen quality
- E.g. no fasting or incorrect fasting time for FBS -
Wrong timing
- E.g. no fasting or incorrect fasting time for FBS -
Insufficient quantity
- QNS -
Suboptimal storage
- Temperature at which we store the sample
- Not all samples are stored at room temperature, some need to be refrigerated or frozen, or there is a time limit to exposure to room temperature
- E.g. For urine sample, prolonged storage can cause bacterial proliferation, decreased glucose, and changed pH levels
Represents a portion or quantity of human material that is tested, examined, or studied t determine the presence or absence of microorganisms or analytes
Clinical Specimen
Routine Handling
Why do some tests require gentle inversions of the specimen tube?
Give an example.
To evenly distribute the additive without compromising quality.
E.g. Light blue top tube containing 3.2% sodium citrate
Routine Handling
Number of inversions depend on ___.
But, it is usually ____.
Number of inversions depend on the type of additive or anticoagulant
But, it is usually 3-10 gentle inversions
TRUE OR FALSE
Inversions may be delayed as long as you invert it within 2 hours.
FALSE
Inversion must not be delayed.
TRUE OR FALSE
Even when collecting multiple tubes, make sure to invert the first tube before proceeding to the next tube
TRUE
Transporting of Specimens
Rough handling of specimens might (4):
- hemolyze the specimens
- activate platelets (creating micro-clots for blood samples inside EDTA tubes)
- affecting the coagulation
- break the glass tube
Transporting of Specimens
Specimen tubes must be transported with the stopper to:
- Avoid spillage of the specimen
- Minimize agitation of the specimen
- Aid in clot formation for serum (plain) tubes
TRUE OR FALSE
As long as there is a stopper, it will guarantee a tight and sealed tube
FALSE
Look out for tube stoppers that suddenly open even without force due to pressure inside the tube.
This allows organisms to survive for isolation
What are these microorganisms?
Transport Medium
- Pathogens
- Contaminants
Purpose of Transport Medium
Maintain viability of samples from collection site to the laboratory
Disadvantage of Transport Medium
Some transport medium allow both pathogens and contaminants to survive.
The presence of contaminants will alter the results. Remember, you are trying to know the pathogen ONLY
Transport medium that does not allow proliferations of organisms
Non-nutritive
TRUE OR FALSE
Transport media to be used is dependent on the suspected pathogen
TRUE
Transport Medium for:
- Bacteria
- Virus
- Parasites
Bacteria
* Cary Blair
* Enterics
Virus
* Virus Transport Medium (VTM)
Parasires
* 10% Formalin to preserve morphology of trophozoites
Transport Medium
Cary Blair
Pathogen:
Specifics:
Cary Blair:
Pathogen: Bacteria
Specifics: Enterics
Enterics Bacteria
Family:
Enterobacteriaceae
Characteristics of the Bacteria family: Enterobacteriaceae
- Gram-Negative Bacilli (Pink stain)
EKESS
- Escherichia coli (E. coli)
- Klebsiela
- Enterobacter
- Shigella
- Salmonella
- Medically-significant; They are fatal when contracted
Transport Medium
Cary Blair
Pathogen:____
Specifics: ____
Pathogen: Bacteria
Specifics: Other bacteria not included in Enterics
- Staphylococcus (Bacteria on skin, nose, and mouth)
Transport Medium: Parasites
Preservative:
Purpose of Preservative:
Transport Medium: Parasites
Preservative:
Purpose of Preservative:
