CLOSTRIDIOIDES DIFFICILE GLUTAMATE DEHYDROGENASE (GDH) ANTIGEN REFLEX TOXIN A/B

Category

Microbiology

Sub Category

Antigen Test

Synonyms/Aliases

C. difficile GDH antigen reflex toxin A & B (clostridioides difficile was formerly called clostridium difficile)

Abbreviations

GDH Reflex Toxin A/B

Type

Profile/ Panel (Bundled Tests)

5 days

5 Days. Positive Results Are Reported As Soon As They Are Obtained. Negative Results Are Reported At 48 Hours (Interim) And 5 Days (Final)

Method

A 2 step testing algorithm I.E. Testing for gdh antigen. If positive, this is followed by testing for toxin a and b. Immunochromatography.

Temp

Room temperature (slides)

Setup

All working days

Components / Parameters

GDH antigen. if positive, reflex testing for toxins A & B.

Pre-analytic Considerations

N/A

Test ordering instructions:

fill out test request form fully & legibly

Sample Requirements

Fill out test request form fully & legibly. clinical history/ indications required inclusive of results of other diagnostic work-up. concurrent CBC printout or CBC order required. concurrent pbf order/ examination required for optimal hematological assessment.

Patient preparation

N/A

Sample type

Stool

Container/ preservative

Sterile Container

Sample volume

50 Grams

Transport Temprature

Refrigirated (1 DAY) or Frozen

Rejection criteria

Labeling issue (unlabeled/ mislabeled); missing request form; incorrect sample type.

Other Instructions

Enquire Befor Sending

Reference intervals

Negative

Clinical Utility

Antibiotic associated diarrhoea & pseudomembranous colitis.

Test Limitations/ Confounders

C. Difficile toxins are labile which may lead to false negative toxin results e.G. Toxins may degrade at room temperature within 1-2 hours. C. Difficile may occur as part of git flora in up to 65% of healthy infants/ 4-14% of healthy adults.

MANTOUX TEST

Category

Microbiology

SubCategory

Mycobacteriology (TB; Mott)

Synonyms/Aliases

Tuberculin test

Abbreviations

N / A

Type

Individual Test

Results

Results ready in 2-3 days

Method

Skin Prick test; 5tu Subcutaneous Injection is given. Reading is obtained 48-72 hours later.

Setup

setup is conducted Daily

Temp

Transportation temprature N/A

Pre-analytic Considerations :

.

Pre-analytic Considerations

For walk in patients only

Test ordering instructions:

Fill out test request form fully & legibly

Patient Preparation

N / A

Sample Requirements

Not applicable

Sample Type

N/A ; this is a skin prick test therefore no sample is collected.

Sample Volume

N/A

Other Instructions

N / A

Reference intervals

As per CDC guidelines

Rejection Criteria

N / A

Clinical Utility

Screening test for latent or active tuberculosis.

Test Limitations/ Confounders :

Interpretation is influenced by factors like HIV status & recent contact with someone known to have TB.

Container / Presavative

N / A

ZIEHL-NEELSEN (ZN STAIN) FOR ACID FAST BACILLI

Category

Microbiology

Sub Category

Microscopy

Abbreviations

ZN STAIN

Synonyms/Aliases

ZIEL-NEELSEN STAIN

Results

Results ready in 3 hours

Test

Individual Test

Method

Staining and microscopy

Setup

All working days

Temp

Transportation Temprature be kept at 2-8ºC

Pre-analytic Considerations

A container that is sterile and leak proof

Component Parameters

N/A

Test Ordering Instructions

fill out test request form fully & legibly. specify sample type/ anatomic site.

Patient Preparation

for sputum specimens only: rinse the mouth with water & cough deeply after taking deep breaths to get a good quality expectorated sputum specimen. collect sputum and not saliva.

Sample Types

variable - sputum, fluid, tissues.

Other Instructions

N / A

Sample Volume

variable - sputum, fluid, tissues.

Sample Requirements

5mL of the sample to the container

Container / Presavative

sterile container

Reference intervals

negative for acid & alcohol fast bacilli (AAFB)

Clinical Utility

diagnosis of mycobacterial infection/ M. tuberculosis

Rejection Criteria

labeling issue (unlabeled/ mislabeled); missing request form; mismatch between request form & sample details.

Test Limitations / Confounders

does not differentiate between mycobacteria species; does not distinguish between viable & dead aafbs in follow-up specimens.

BLOOD CULTURE AND SENSITIVITY

Category

Microbiology

Sub Category

Microscopy/ Culture/ Sensitivity (M/c/s)

Synonyms/Aliases

Blood Culture

Abbreviations

Blood C/S

Type

Profile/ Panel (Bundled Tests)

5 days

5 Days. Positive Results Are Reported As Soon As They Are Obtained. Negative Results Are Reported At 48 Hours (Interim) And 5 Days (Final)

Method

Culture And Antibiotic Sensitivity Testing (Where Indicated) Using Conventional Methods For Identification & Kirby Bauer Method For Antibiotic Susceptibility Testing.

Temp

Room temperature (slides)

Setup

All working days

Components/Parameters

pathogen isolation, identification & reporting of appropriate antibiotics as applicable.

Pre-analytic Considerations

N/A

Sample Requirements

Fill out test request form fully & legibly. clinical history/ indications required inclusive of results of other diagnostic work-up. concurrent CBC printout or CBC order required. concurrent PBF order/ examination required for optimal hematological assessment.

Patient preparation

Collection Should Preferably Be Done Before Initiation Of Antibiotics.

Sample type

Whole Blood.

Container/ preservative

Blood Culture Bottles (Aerobic & Anerobic Set For Adults; Aerobic Bottle For Infants & Young Children).

Sample volume

3 ML

Rejection criteria

Labeling Issue (Unlabeled/ Mislabeled); Missing Request Form; Incorrect Preservative/ Container; Frozen Sample.

Other Instructions

if additional tests are required, obtain the relevant samples & list them on the request form e.g. flow Cytometry (EDTA & Heparin Vacutainer, 3ml each), Cytogenetics (Sodium Heparin Vacutainer), Culture (Blood Culture Bottles) etc.

Reference intervals

No Growth Obtained/ No Pathogens Isolated.

Clinical Utility

PYREXIA Of Unknown Origin.

Test Limitations/ Confounders

Prior Exposure To Antibiotics, Refrigeration Of Samples & Under/ Overinoculation Of Blood Culture Bottles (Incorrect Sample Volume) Can Result In False Negative Cultures. Skin Commensals May Be Grown As Contaminants.

Other

Draw Using Aseptic, Non-touch Technique; Blood Cultures Are The First To Be Collected In The Venepuncture Order Of Draw; Do Not Refrigerate; Transport Immediately (At Room Temperature) To The Lab For Immediate Incubation; For Adults, 2-3 Blood Culture Sets (Aerobic & Anaerobic Bottle Set) Are Recommended; For Infants & Young Children, Aerobic Bottles Suffices.

HIGH VAGINAL SWAB (HVS) MICROSCOPY, CULTURE AND SENSITIVITY

Category

Microbiology

SubCategory

Microscopy/ Culture/ Sensitivity (M/C/S)

Synonyms /Aliases

HVS Culture & Sensitivity

Abbreviations

HVS C/S; HVS M/C/S

Test

Profile/ panel (bundled tests)

Method

Culture and antibiotic sensitivity testing (where indicated) using conventional methods

Results

Results ready after 3 days

Setup

The setup is conducted Daily

Transport

the transport temprature should be set at 2-8ºC

Component / Parameters

Pathogen isolation, identification & reporting of appropriate antibiotics as applicable

Pre-analytic Considerations

N / A

Patient Prepations

N / A

Sample Type

HVS SWABS (2)

Container / Presavative

Vaginal swab in sterile transport media

Sample Requirements

Vaginal swab in sterile transport media

Sample Volume

N / A

Rejection Criteria

Labeling issue (unlabeled/ mislabeled); missing request form; incorrect preservative/ container; dry swabs.

Other Instructions

HVS collection can be done on site but attracts additional charges.

Reference intervals

No growth obtained/ no pathogens isolated

Clinical Utility

Investigation of infections of the female Genital tract E.G. Bacterial vaginosis, Candidiasis, Trichomoniasis etc.

Test Limitations / Confounders

Not suitable for identifying or culturing genital pathogens such as Treponemes, Haemophilus Ducreyi, Calymmatobacteria, Mycoplasma, Chlamydia, HSV 1 & 2.