When Is It Appropriate To Ask The Laboratory To Perform An Acid-fast Stain

1. Prepare two fixed smears of each culture and two of the simulated sputum. In practice, the smears are fixed with methanol for one minute or are heat-fixed at 65 to 75°C to be certain any tuberculosis bacilli present are killed. To make smears of the agar slant culture, first place a drop of water on the slide, and then emulsify a small amount of the colonial growth in this drop.

2. Ring and code one slide of each pair with your marking pencil or pen, as usual.

3. The other slide of each pair must be ringed and coded with a diamond pencil. This device scratches the glass indelibly, so that the marks remain even during the prolonged staining process.

4. Gram stain the set of slides marked with the pencil or pen in step 2.

5. Stain the diamond-scratched slides by the Kinyoun technique:

a. Place the slides on a slide rack extended over a metal staining tray, if available.

b. Cover smear with a 2 X 3-cm piece of filter paper to hold the stain on the slide and to filter out any undissolved dye crystals.

c. Flood the slide with concentrated carbolfuchsin solution and allow to stand for five minutes.

d. Use forceps to remove filter paper strips from slides and place the strips in a discard container. Rinse slides with water and drain.

e. Cover smears with acid-alcohol solution and allow them to stand for two minutes.

f. Rinse again with water and drain.

g. Flood smear with methylene blue and counterstain for one to two minutes.

6. Examine all slides under oil immersion and record observations under Results. See colorplate 9 for examples.

Morello-Mizer-Granato: I I. Basic Techniques of I 3. Differential Stains I I © The McGraw-Hill

Laboratory Manual and Microbiology Companies, 2003 Workbook in Microbiology, 7/e

Results

Name of Organism

Visible in Gram Stain* (Yes, No)

Gram-Stain Reaction (If Visible)

Visible in Acid-Fast Stain (Yes, No)

Color in Acid-Fast Stain

Acid-Fast Reaction (If Visible)

Cultures

Sputum specimen (describe organism)

*Note: Some saprophytic mycobacteria may stain weakly gram positive or appear beaded in Gram-stained smears.

*Note: Some saprophytic mycobacteria may stain weakly gram positive or appear beaded in Gram-stained smears.

Questions

1. What is a differential stain? Name two examples of such stains.

2. Is a Gram stain an adequate substitute for an acid-fast stain? Why?

3. When is it appropriate to ask the laboratory to perform an acid-fast stain?

Morello-Mizer-Granato: I. Basic Techniques of Laboratory Manual and Microbiology

Workbook in Microbiology, 7/e

4. In light of the clinical history (p. 41) and your observations of the Gram and acid-fast smears, what is your tentative diagnosis of the patient's illness? How should this preliminary laboratory diagnosis be confirmed?

5. Are saprophytic mycobacteria acid fast?

6. Does the presence of acid-fast organisms in a clinical specimen always suggest serious clinical disease?

7. How should the acid-fast stain of a sputum specimen from a patient with suspected pulmonary Nocardia infection be performed?

Morello-Mizer-Granato: I I. Basic Techniques of I 3. Differential Stains I I © The McGraw-Hill

Laboratory Manual and Microbiology Companies, 2003 Workbook in Microbiology,

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Responses

  • aarne
    When is it appropriate to perform an acidfast stain?
    8 years ago
  • anniina
    When is it appropriate to ask the laboratory to perform an acidfast stain?
    8 years ago
  • Stanislao Panicucci
    Does presence of acidfast organisms always suggest serious clinical disease?
    8 years ago
  • VEIJO
    When is it appropriate to ask the laboratory to perform an acid fast stain?
    8 years ago
  • wilibald
    When is it apprpriate to ask for an acid fast stain to be performed?
    8 years ago
  • heribald
    When is it appropriate to ask the laboratory to perform an acid faast stain?
    8 years ago
  • Marie
    When is it appropriate to ask the lab?
    8 years ago
  • gaetana siciliani
    When is it appropriate to ask the laboratory to perfrom an acidfast stain?
    8 years ago
  • ISOBEL
    What is a differential stain name two examples?
    8 years ago
  • EDGARDO
    Is a gram stain an adequate substitute for an acid fast stain?
    8 years ago
  • bernardo
    Are saprophytic mycobacteria acid fast?
    8 years ago
  • paciano
    When is appropriate to perfor an acid fasst stain?
    8 years ago
  • Cesare
    What is the tentative diagnosis of the patient s illness acid fast stain?
    7 years ago
  • Martha
    Does the presence of acid fast organisms always suggest a serious disease?
    6 years ago
  • diana
    When is it appropiate to ask a lab to perform an acid fast stain?
    4 years ago
  • jana
    When is it apropriate to ask the laboratory to perform an acid fast stain?
    4 years ago
  • libera maria
    When is it appropriate to perform acid fast staining?
    3 years ago
  • Eve
    When is it appropraite to perform an acid fast stain?
    3 years ago
  • Lelio Marcelo
    When to ask for the lab for acid fast stain of patients sputum?
    2 years ago
  • JAANA
    Is gram staining an adequate substitute for acid fast staining?
    2 years ago
  • Isobel
    When is it appopriate to perform an acidfast stain?
    2 years ago
  • esther
    When is it appropriate to ask the labratory tp perform an acidfast stain?
    7 months ago

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