Microscopic examination of materials from infected sites and Lab examination of specimens

what is one rule for swabs

always collect 2

• one for direct smear

• one for culture 

what should a specimen label contain?

• patient name

• ID number

• DOB

• culture site/anatomic site (R/L)(Upper/Lower)

• date of collection

• time of collection

when should specimens be transported to the lab?

within 2 hours of collection

• if less than, need to use preservatives or transport media

what preservative is used for urine

boric acid

what preservative is used for feces

polyvinyl alcohol, buffered formalin, Cary-Blair transport media

what preservative is used for blood, bone marrow, and synovial fluid?

anticoagulants

• sodium polyanethol sulfonate (SPS)

• heparin

• ethylenediamine tetraacetic acid (EDTA)

• citrate/citric acid/dextrose (ACD)

what are some reasons you would reject a specimen?

• mislabeled/unlabeled

• wrong transport container or leakages

• quantity not sufficient (QNS)

• transported >2 hrs to lab w/o preservatives

• specimen preserved wrong

commensalism

microorganism benefit, host not harmed

mutualism

microorganism and host benefit

parasitism

microorganism benefits, host is harmed

What two types of cells are used to calculate the Q-score of a sputum sample?

neutrophils & squamous epithelial

what is the criteria for a sputum sample for culture

10-25 epithelial cells per low power field

> 25 WBCs per low power field

what are some rejection criteria for sputum samples

< 25 WBCs/LPF

> 10 squamous epithelial cells or mixed bacteria/LPF

how many stool samples do you need if you’re testing for a bacterial infection?

3 samples; 1 stool per day over 3 days

how many stool samples do you need if you’re testing for a parasite infection?

3 samples over 10 days

what is a rule for blood culture collection

need 2 sets with a difference of 15 mins from the different arm

what specimens take most priority?

CSF, blood, amniotic fluid, pericardial fluid

what specimens take 2nd priority?

unpreserved specimens, other body fluids, sputum, feces, wounds, tissue

what specimens take 3rd priority?

urine, catheter tip, tissue for quantitation

what specimens take 4th priority?

preserved specimens, swabs in holding medium

what media should CSF be inoculated to and should a gram stain be performed?

BAP, CHOC, THIO. Perform Gram Stain

what media should a wound culture be inoculated to and should a gram stain be performed?

BAP, CHOC, MAC or EMB, ANA, THIO. perform gram stain

what media should a clean catch urine be inoculated to and should a gram stain be performed?

BAP, MAC. No gram stain required

what media should sputum be inoculated to and should a gram stain be performed?

BAP, MAC, CHOC. perform gram stain

what media should blood be inoculated to and should a gram stain be performed?

blood culture bottles

what media should feces be inoculated to and should a gram stain be performed?

BAP, MAC or EMB, HE or XLD, CAMPY, SMAC