Specimen Handling Protocols Flashcards
Specimen Handling Protocols
-For clinical, environmental, or research studies the results are only as good as the specimen you start with
-A poorly collected or processed specimen is unusable and will delay the identification of the pathogen
>Patients are the ones that will be affected
-Pure cultures are needed to identify organisms
>Most specimens sent to lab will be mixed cultures
Procedures for Clinical Specimen Collection
- The specimen must be collected before starting antimicrobial therapy
- The specimen must be representative of the condition
- Adequate amounts of material must be collected
- Proper transport is vital
- A series of samples may be necessary
- Aseptic technique and sterile containers must be used
- Specimens must be kept moist
- Specimens must be labeled properly
Procedures for Clinical Specimen Collection: The specimen must be collected before starting antimicrobial therapy
bacteria will disappear 2 hours after the start of therapy
Procedures for Clinical Specimen Collection: The Specimen must be representative of the condition
Saliva versus sputum
Procedures for Clinical Specimen Collection: Adequate amounts of material must be collected
multiple tests may be necessary
Procedures for Clinical Specimen Collection: Proper transport is vital
- some organisms are temperature and oxygen sensitive
- don’t allow specimen to sit out
Procedures for Clinical Specimen Collection: A series of samples may be necessary
- blood cultures require 6-8 samples
- sputum samples require 2 per day for 3 days
Procedures for Clinical Specimen Collection: specimens must be kept moist
- use transport media
- check expiration date on tubes and swabs
Blood Cultures
-Blood is injected into bottles that contain culture media
-Pathogens which have invaded the bloodstream can be detected very quickly
>89% within 24 hours
>97% within 48 hours
>Septicemia, Enteric Fever, Bacterial endocarditis
-Bottles are continuously monitored
-Readings are transmitted to a computer compiler
Blood Cultures: Detect
- Septicemia
- Enteric Fever
- Bacterial endocarditis
Urine Culture Colony Counts
-When performing a urine colony count both the number of cells and the type of bacteria growing is important
>Quantitative= number of cells
>Qualitative= type of bacteria (Genus and Species)
Urine Cultures
- The urine is collected in a sterile container using the clean catch, midstream method
- A calibrated loop (0.001 ml) is used to inoculate the plate
- A single line is drawn down the center of the plate, and then is spread over the entire plate perpendicularly
- After the plate is incubated you can count the number of colonies on the plate and determine the amount of bacteria in the sample
- Number of colonies X dilution factor;
ex: 40 colonies X 1000= 40000 microbes/ml of urin
Formula for determining the amount of bacteria in the sample of urine (Quantitative Evaluation)
Number of colonies X dilution factor
ex: 40 colonies (number visually counted on plate) X 1000= 40000 microbes/ml of urine
- 1000= dilution factor
Quantitative Evaluation of Urine
- Multiply the number of colonies by the dilution factor (loop size) to get the number of bacteria in 1 ml of urine
ex: 40 colonies X 1000=40000 microbes/ ml of urine
Quantitative Evaluation Chart
Colonies/0.001 ml Microbes/ml of urine Significance
0-9 0-9000 no growth
10-99 10,000-99,000 infection
100+ 100,000+ Acute Infection
