Dx and Lab methods Flashcards
Blood culture
Collection: Blood draw, 2-3 samples from dif sites
organism: bacteria/fungi. no viruses
interpretation: if 2+ cultures pos for same bacteria, means pt. has infection with that organism
Sputum culture
Collection: sample coughed up into sterile cup, want deep cough to get sample from base of lungs
Organisms: bacteria
Interpretation: Gram stain, then placed in media and incubated
Viral culture/fluorescent microscopy
Collection: via blood sample or tissue sample
Organisms: Viral antigens from HSV, VZV, adenovirus, MCV, etc.
Interpretation: virus grown in living cells
-growth measured by antigen detection methods
- Measure amount of growth
Acid fast bacilli stain (AFB)
Collection: x3 sputum samples collected early in the morning on different days
Organisms: TB and other mycobacterium
Interpretation: AFB smear: smear, stain, quick and good while cultures are pending
- Molecular tests for TB: 24hrs, detects genetic parts of TB
- AFB cultures: more sensitive but takes 2 weeks
- Susceptibility testing: test for susceptibility to Abx
Fungal culture
Collection: (First step to diagnose fungal infection
- can be swabbed from superficial fungal infections
- systemic infections can be tested from blood, urine, sputum, bone or tissue biopsy
Organism: fungi
Interpretation: Grow, may be weeks..
sputum gram stain
Collection: spit sputum into sterile container
Organism: bacteria and some fungi
Interpretation: smear and stain, gram pos or neg, fungi may be seen and reported as well
mycoplasma serology
Collection: Blood sample
Organism: Mycoplasma species, (Mycoplasma pneumonia)
Interpretation: ELISA, definitive diagnose requires paired specimens obtained 2-4 weeks apart
- Looking for both IgM and IgA increased levels
cold agglutinin
Collection: via a blood sample, must be kept within temp range.
Organism: To ID cause of hemolytic anemia and dx. cold agglutinin
Interpretation: Results reported as a titer with higher numbers meaning more autoantibodies present
