Concept about Blood Culture – Basic microbiology, parasitology, and immunology; nature, reproduction, growth, and transmission of common microorganisms and parasites in Bangladesh; prevention including universal precaution and immunization, control, sterilization, and disinfection; and specimen collections and examination. Students will have an understanding of common organisms and parasites caused human diseases and acquire knowledge about the prevention and control of those organisms.
Concept about Blood Culture
Different Culture
Method/Steps of Culture:
- Collection of specimen in a sterile container.
- Transport or storage without killing microorganisms.
- Inoculation in appropriate medium.
- Incubation of the inoculated medium at optimum temperature, in correct atmosphere for an adequate period.
Definition of Blood Culture
Blood culture is a test designed to detect if microorganisms such as bacteria and fungi are present in blood. A sample of blood obtained using sterile technique is placed in a culture media and incubated in a controlled environment for 1 to 7 days.
Or
A blood culture is a laboratory test to check for bacteria or other germs in a blood sample.
Indication of Blood Culture
- Enteric fever.
- Septicaemia.
- Bacteremia.
- Meningitis.
- Pyrexia of unknown origin.
- Bacterial infective endocarditis.
- Osteomyelitis.
- Brucellosis
- Urinary tract infection (If there is fever, rigors or evidence of septic shock).
Media Used For Blood Culture
The following media are used to culture a blood sample-
- Tryptic soya (Tryptone soya, trypticase soya) broth.
- Diphasic tryptone soya medium.
- Bile salt broth with or without Gention violet.
- Thioglycolate broth for growth of anaerobes.
- Brain heart infusion broth.
Subculture done in:
- Blood agar media
- Mac Conkey’s agar media
- Chocolate agar media.
Methods of Blood Culture
Blood culture can be done in three processes-
- Traditional method – Using liquid media on biphasic media
- Lytic method – After processing in lytic solution in solid media
- Automated – very rapid (within 6 hour)
Procedure of Blood Collection for Blood Culture in a Laboratory
A. Materials:
- Tourniquet.
- Small mackintosh.
- Syringes: 3ml 5ml, 10ml.
- No 20 Gauge needles.
- Alcohol swabs
- Disposable gloves.
- Specimen container- test tube or bottle.
- Laboratory requisition formuloni alla led D
- Sterile gauze pads (2″X2″)
- Adhesive tap
B. Procedure:
1. Check the physician’s order, progress, notes, and nursing care plan,
2. Identify the patient.
3. Explain the procedure to the patient.
4. Collect and prepare equipment.
5. Ensure patient’s privacy.
6. Wash and dry hands.
7. Put on clean, disposable gloves.
8. To avoid hemolysis, the needle used for venepuncture should have a short bevel, the syringe and needle must be dry, and the container into which the specimen is placed must be dry.
9. For some tests whole, clotted blood is required, whilst for others it should be anti- coagulated, so that the laboratory may obtain the fraction of the blood for examination that they require.
10. Each laboratory should issue specimen bottles containing the correct anticoagulant for each test, with instructions as to the quantity of blood required to bom quod
11. Heparin, potassium oxalate and sodium citrate are fairly common anticoagulants.
12. For blood sugar estimation fluoride is added to the tube to prevent the disappearance of the sugar from the blood. nalq mas grizin best ralne asisizada als las
13. Once the blood has been added to the anti-coagulant, it must be inverted gently so that it is thoroughly mixed with the specimen.
14. When sending blood for examination, care must be taken to avoid haemolysis of the specimen, for haemolysis renders the specimen useless.
15. Shaking causes haemolysis.
16. Document the procedure appropriately
Standard collection protocol
- Collect upto 3-4 sets of blood culture bottles.
- Two blood culture bottles in each set.
- Obtain 5 ml blood per bottle.
- Draw from upto 3 different venipuncture sites.
- Space blood collections by 1 hour intervals.
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