LAB 304 Lecture \ 4

1. Samples LAB 304Lecture \ 4

2. Learning objectives • To know what is the meaning of blood culture. • To recognize types of urine samples . • To learn procedure of urine specimen collection. • To learn procedure of sputum specimen collection. • To learn some information about fecal specimen collection.

3. Blood culture

4. Blood culture • Blood culture : is a microbiological culture of blood. It is employed to detect infections that are spreading through the bloodstream (such as bacteremia or  septicemia amongst others). This is possible because the bloodstream is usually a sterile environment. • N.B : blood does not have a normal microbial flora .

5. Blood culture • Whenever possible blood should be collected before antimicrobial treatment has started . 1- when the patient has recurring fever collect the blood as the temperature begins to rise . 2- for other patients collect the blood as soon as possible after receiving the request . * To increase the chance of isolating a pathogen it is usually recommended that at least two specimens are collected at different times.

6. Urine collection • Untimed urine sample (random) ( single sample ) • Timed urine sample ( 24 H sample ) • First Morning Specimen • Midstream Clean Catch Specimen • Catheter Collection Specimen • Pediatric Specimen

7. Urine collection 1- Random Specimen • This is the specimen most commonly sent to the laboratory for analysis, primarily because it is the easiest to obtain and is readily available. • This specimen is usually submitted for urinalysis and microscopic analysis, although it is not the specimen of choice for either of these tests. • Random specimens can sometimes give an inaccurate view of a patient's health if the specimen is too diluted and analytic values are artificially lowered.

8. Urine collection 1- Random Specimen • As the name implies, the random specimen can be collected at any time. Although there are no specific guidelines for how the collection should be conducted, avoiding the introduction of contaminants into the specimen is recommended. This requires explicit instructions to patients so that they do not touch the inside of the cup or cup lid.

9. Urine collection 2- Timed Collection Specimen • Among the most commonly performed tests requiring timed specimens are those measuring creatinine, urine urea nitrogen, glucose, sodium, potassium and other analytes that are affected by diurnal variations. • A timed specimen is collected to measure the concentration of these substances in urine over a specified length of time.

10. Urine collection 2- Timed Collection Specimen • You should collect every drop of urine during each 24-hour period. It does not matter how much or little urine is passed each time, as long as every drop is collected. • Begin the urine collection in the morning after you wake up, after you have emptied your bladder for the first time. • Urinate (empty the bladder) for the first time and flush it down the toilet. Note the exact time (e.g, 5:00 AM). You will begin the urine collection at this time.

11. Urine collection 2- Timed Collection Specimen • Collect every drop of urine during the day and night in an empty collection bottle. Store the bottle at room temperature or in the refrigerator. • If you need to have a bowel movement, any urine passed with the bowel movement should be collected. • Finish by collecting the first urine passed the next morning, adding it to the collection bottle. This should be within ten minutes before or after the time of the first morning void on the first day (which was flushed). In this example, you would try to void between 4:50 and 5:10 on the second day.

12. Urine collection 2- Timed Collection Specimen • It is not recommended that the patient void directly into the 24 hour collection container due to the preservative acid content inside the container. • The patient is encouraged to void into a separate (beaker style collection with pour spout ) cup and pour the contents into the 24 hour collection container during the collection process.

13. Urine collection 3- First Morning Specimen • This is the specimen of choice for urinalysis and microscopic analysis, since the urine is generally more concentrated (due to the length of time the urine is allowed to remain in the bladder) . • Also called an 8-hour specimen, the first morning specimen is collected when the patient first wakes up in the morning, having emptied the bladder before going to sleep.

14. Urine collection 4- Midstream Clean Catch Specimen • This is the preferred type of specimen for culture and sensitivity testing because of the reduced incidence of cellular and microbial contamination. • Patients are required to first cleanse the urethral area with soap . The patient should then void the first portion of the urine stream into the toilet. These first steps significantly reduce the opportunities for contaminants to enter into the urine stream. The urine midstream is then collected into a clean container . This method of collection can be conducted at any time of day or night.

15. Urine collection

16. Urine collection 5- Catheter Collection Specimen • This assisted procedure is conducted when a patient is bedridden or cannot urinate independently. The healthcare provider inserts a Foley’s catheter into the bladder through the urethra to collect the urine specimen.

17. Urine collection 6- Pediatric Specimen • For infants and small children, a special urine collection bag is adhered to the skin surrounding the urethral area. Once the collection is completed, the urine is poured into a collection cup or transferred directly into an evacuated tube with a transfer straw.

18. Sputum collection • Specimen required is From the lower respiratory tract expectorated by deep coughing . • Sputum specimen collection can be either self-expectorated or mechanically obtained. • Sputum samples should be collected in the morning before breakfast if possible , because sputum collects during the night.

19. Sputum collection PROCEDURE 1- Wash hands thoroughly 2- Assemble necessary equipment. 3- Confirm the patient’s identity using two patient identifiers. 4- Tell the patient that : * you will collect a specimen of sputum (not saliva) and explain the procedure. * The cup is very clean. So Don’t open it until you are ready to use it.

20. Sputum collection PROCEDURE 5- Instruct the patient to sit in a chair or at the edge of the bed. If the patient cannot sit up place him in high Fowler’s position. * Place the head of the bed at 30° for semi-Fowler's, 45° to 60° for Fowler's, and 90° for high Fowler's

21. Sputum collection PROCEDURE 6- Ask the patient to rinse his/ her mouth with water (avoid mouthwash solution or toothpaste). 7- Tell patient to cough deeply and expectorate directly into the specimen container. At least 15 ml is needed to identify the causative organism.

22. Sputum collection

23. Sputum collection PROCEDURE 8- Cap the container and if necessary, clean its exterior.

24. Sputum collection • Purpose : For the detection of the causative agent of pneumonia, bronchitis, lung abscess or tuberculosis . Examples of common causative agents of bacterial pneumonia: • Streptococcus pneumoniae, • Haemophilusinfluenzae, • Staphylococcus aureus, • Klebsiellapneumoniae, • Escherichia coli, and • Pseudomonas aeruginosa.

25. Fecal sample • Collect the stool in a dry, clean, leak-proof container. • Make sure no urine, water, soil or other material gets in the container. • Insure that the specimen containers are sealed well.  Reinforce with parafilm or other suitable material. • Insert the container in a plastic bag. • Certain drugs and compounds will render the stool specimens unsatisfactory for examination.  The specimens should be collected before these substances are administered, or collection must be delayed until after the effects have passed.

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