Specimen collection 200 QSPg 6-9

Calcium alginate or wooden shafts

What materials should strictly NOT be used as swab shafts or materials when collecting Neisseria or for PCR tests?

Within 2 hours at room temperature.

At what temperature and within what timeframe should standard transport media (like Amies or Stuart) be transported to the lab at room temperature?

Refrigerated at 2–8°C for up to 24 hours.

What is the storage temperature and maximum allowable duration for refrigerated swab specimens in standard transport media?

Measure the distance from the nostril to the outer opening of the ear.

How is the insertion distance measured prior to collecting a Nasopharyngeal Swab (NPS)?

Horizontally back along the floor of the nasal cavity until resistance is met (posterior nasopharynx).

How is a flexible mini-tip swab inserted during NPS collection?

Universal Transport Medium (UTM) or Viral Transport Medium (VTM).

What transport media are recommended for viral culture or PCR when collecting an NPS?

Stable for 48–72 hours.

How long are viral transport media (UTM/VTM) stable for NPS specimens?

Amies with charcoal or Regan-Lowe.

What specialized transport media are used for bacterial culture of Bordetella pertussis from an NPS?

2–8°C.

At what temperature should NPS specimens in UTM/VTM be stored or transported?

Nasopharyngeal Swab (NPS).

What is the specimen of choice to detect the carrier state of N. meningitidis, B. pertussis, H. influenzae, S. aureus (MRSA), and C. diphtheriae?

Dacron or rayon with plastic shafts.

What is the best type of swab material and shaft for a throat culture?

It is toxic to viruses.

Why is calcium alginate avoided for viral specimen collection?

Plastic dacron or rayon swab, or nylon flocked swabs.

What type of swab is considered the best for recovery of genital specimens, offering up to 90% recovery?

Cotton/wood is toxic to Neisseria and inhibits culture/recovery.

Why should wooden cotton swabs NOT be used for genital specimens or Neisseria?

Viridans Streptococci / alpha-hemolytic Streptococci.

What is the most abundant flora present in the throat?

Streptococcus pyogenes / Group A beta-hemolytic Streptococci.

What is the most common bacterial pathogen found in throat specimens?

Throat, oral cavity, and nasopharynx.

What structures comprise the upper respiratory tract?

Larynx, trachea, bronchi, and alveolar sacs.

What structures comprise the lower respiratory tract?

MAC, BAP, CAP, and Amies.

Which basic media are listed for routine respiratory tract processing?

Modified Thayer Martin (MTM) and Thioglycollate broth (Thio).

What selective media/broth are added specifically for processing throat swabs?

Dacron, rayon, and calcium alginate (except for Neisseria).

In bacterial cultures, which swab materials are acceptable?

Dacron, rayon, and cotton.

In viral cultures, which swab materials are acceptable?

Sterile, screw-cap container.

What type of container should be used for collecting urine specimens?

Wash hands, cleanse periurethral area with soap/water or wipes, discard initial stream, and collect the midstream portion.

What are the key collection steps for a Midstream Clean-Catch (MSCC) urine sample?

Aseptically aspirate urine from the sampling port using a sterile syringe/needleless adapter.

How is urine collected from an indwelling catheter?

It leads to specimen contamination and inaccurate colony counts.

Why should urine never be collected from a catheter collection bag/mug?

Straight catheterization or suprapubic aspirate.

What collection types are preferred for sterile urine collection in infants and young children?

10–15 mL.

What is the standard recommended volume for a first morning urine specimen?

Within 2 hours.

Within what timeframe must unpreserved urine be transported to the laboratory at room temperature?

Boric acid transport tube.

What preservative transport tube is used if urine transport exceeds 2 hours?

Up to 24–48 hours.

How long can boric acid preserve bacterial colony counts in urine at room temperature?

Escherichia coli.

What is the primary cause of Urinary Tract Infections (UTIs)?

Staphylococcus saprophyticus.

What is the second most common cause of UTIs in young sexually active females?

$1\,\mu\text{L}$ ($0.001\,\text{mL}$) or $10\,\mu\text{L}$ ($0.01\,\text{mL}$).

What calibrated loop sizes are used when performing a quantitative urine colony count?

Number of colonies counted $\times 1000 = \text{colony count/mL of urine}$.

What is the formula to compute colony count per mL of urine using a $1\,\mu\text{L}$ ($0.001\,\text{mL}$) loop?

$20,000\text{ CFU/mL}$.

If 20 colonies are counted using a $1\,\mu\text{L}$ calibrated loop, what is the reported colony count per mL?

Number of colonies counted $\times 100 = \text{colony count/mL of urine}$.

What is the formula to compute colony count per mL of urine using a $10\,\mu\text{L}$ ($0.01\,\text{mL}$) loop?

$2,000\text{ CFU/mL}$.

If 20 colonies are counted using a $10\,\mu\text{L}$ calibrated loop, what is the reported colony count per mL?

> 100,000\text{ CFU/mL}.

What colony count threshold is generally considered significant bacteriuria?

> 50,000\text{ CFU/mL}.

What colony count threshold is considered indicative of a UTI?

< 10,000\text{ CFU/mL}.

Urine colony counts below what value are considered contaminants?

Presence of bacteria in urine at a concentration > 100,000\text{ CFU/mL}.

Define bacteriuria in terms of colony count.

48 hours.

After how many hours is a final urine culture result typically read/reported?

MacConkey Agar (MAC) and Blood Agar Plate (BAP).

What media are routinely used for urine cultures?

Pneumonia and Tuberculosis (TB).

What lower respiratory tract infections are routinely diagnosed via sputum culture?

Geckler Criteria.

What system uses Squamous Epithelial Cells (SECs) vs PMNs to evaluate sputum specimen quality?

> 10\text{ SECs/LPF}.

According to CLSI quality assessment, what count of squamous epithelial cells leads to sputum rejection?

Heavy saliva contamination.

What does a high squamous epithelial cell count in a sputum sample indicate?

Rinse mouth with water to clear oral debris and deep cough from the lungs.

What pre-collection instruction should be given to a patient prior to expectorating sputum?

First morning specimen.

What type of sputum specimen is ideal for culture?

Mouthwash and spit/saliva.

What substances are explicitly NOT allowed during sputum collection?

3–5 mL of thick, purulent sputum.

What is the recommended volume for an expectorated sputum sample?

Administration of nebulized hypertonic saline by a respiratory therapist.

How is induced sputum obtained if a patient cannot produce it spontaneously?

$< 10\text{ squamous epithelial cells}$ and $> 25\text{ PMNs per LPF}$.

Under direct microscopic examination, what cell counts define an acceptable sputum specimen?

> 25\text{ squamous epithelial cells} and < 10\text{ PMNs per LPF}.

Under direct microscopic examination, what cell counts indicate a saliva sample that must be rejected?

Direct Gram stain.

What routine microscopic stain is performed on all sputum samples?

Saliva, oropharyngeal secretions, and sinus drainages from nasopharynx.

Name three upper respiratory drainage/secretions that cause sputum sample rejection.

Room temperature ($25^\circ\text{C}$).

What is the transport temperature for sputum samples?

Refrigerate at 2–8°C to suppress normal flora overgrowth.

If processing of a sputum sample is delayed beyond 2 hours, how should it be stored?

NALC (N-acetyl-L-cysteine) and NaOH digestion-decontamination.

What is the gold standard method for TB culture processing?

Digestion agent to lyse the mucus.

What is the role of N-acetyl-L-cysteine (NALC) in TB culture processing?

Decontaminating agent.

What is the role of NaOH in TB culture processing?

Löwenstein-Jensen (LJ) medium.

What culture medium is used for Mycobacterium tuberculosis?

0.

In Bartlett's Classification, what grade is assigned to < 10 neutrophils/LPO?

+1.

In Bartlett's Classification, what grade is assigned to 10–25 neutrophils/LPO?

+2.

In Bartlett's Classification, what grade is assigned to > 25 neutrophils/LPO?

+1.

In Bartlett's Classification, what grade is added for the presence of mucus?

-1.

In Bartlett's Classification, what grade is assigned to 10–25 epithelial cells/LPO?

-2.

In Bartlett's Classification, what grade is assigned to > 25 epithelial cells/LPO?

Scores of 0 or less.

In Bartlett's Classification, what total score results in specimen rejection?

Lack of inflammation or presence of saliva.

What does a total score of 0 or less in Bartlett's Classification indicate?

Total score > 1.

What total score in Bartlett's Classification indicates an acceptable sputum specimen?

Alveolar Macrophages (AM) and Columnar Cells (CC).

Aside from SECs and PMNs, what other two cell types are scanned to determine sputum suitability?

15% sodium chloride and 10% glycerin for approximately 10 minutes.

What solution composition and duration are used to obtain aerosol-induced sputum specimens?

Fewer than $10\text{ cells/lpf}$.

In microscopic reporting, what cell count corresponds to the term "Few"?

10 to $25\text{ cells/lpf}$.

In microscopic reporting, what cell count corresponds to the term "Moderate"?

Greater than $25\text{ cells/lpf}$.

In microscopic reporting, what cell count corresponds to the term "Abundant"?

Polymorphonuclear neutrophils (PMNs).

Which cell type seen in sputum is specifically associated with acute bacterial pneumonia?

Alveolar macrophages and columnar cells.

The presence of which two cell types confirms that a lower respiratory tract specimen was collected properly?

Pseudomonas aeruginosa, Klebsiella pneumoniae, Mycoplasma pneumoniae, Legionella pneumophila, Staphylococcus aureus, Haemophilus influenzae, and Streptococcus pneumoniae.

Name seven significant pathogens isolated from sputum.

Clean, dry, leak-proof container or bedpan (wide mouth).

Into what type of container should freshly passed stool be collected?

Urine, water, and toilet paper.

What three substances must be avoided during stool collection to prevent contamination?

Reserved primarily for infants or patients unable to produce a stool sample.

When are rectal swabs permissible for stool collection?

Insert swab past the anal sphincter, gently rotate, and verify visible fecal staining.

How is a rectal swab properly collected?

5–10 mL of liquid stool or a pea-to-walnut-sized portion of solid stool.

What is the required volume/amount for stool samples?

To prevent testing for community-acquired diarrhea instead of C. difficile or nosocomial pathogens.

Why are stool samples collected > 3 days post-hospitalization rejected?

Within 2 hours.

Within what time frame must unpreserved stool be delivered to the laboratory?

Cary-Blair Medium.

What transport medium is used for stool specimens delayed beyond 2 hours?

3 specimens collected once a day for 3 days.

What is the collection schedule for stool specimens suspected of bacterial infection?

3 specimens collected within 10 days.

What is the collection schedule for stool specimens suspected of parasitic infection?

Salmonella, Shigella, and Campylobacter.

Which three bacterial pathogens are routinely included in a routine stool culture?

Vibrio, Plesiomonas, Escherichia coli O157:H7, Aeromonas, and Yersinia.

Name four additional fecal pathogens that may be requested or cultured.

Cytotoxin test.

What specific test must be performed if Clostridium difficile is suspected in stool?

MacConkey Agar (MAC) and Blood Agar Plate (BAP).

What screening media are used for stool specimens?

SS Agar (SSA) and Hektoen Enteric Agar (HEA).

Which selective/differential media are used for isolating Salmonella and Shigella?

Thiosulfate Citrate Bile Salt Sucrose (TCBS) Agar.

What selective media is used to isolate Vibrio species?

Cefsulodin Irgasan Novobiocin (CIN) Medium.

What selective medium is used to isolate Yersinia enterocolitica?

Selenite F broth and Alkaline Peptone Water (APW).

Name two enrichment broths used for stool specimens.

Normal fecal microflora makes interpretation uninformative and misleading.

Why should direct Gram staining NOT be performed on routine stool specimens?

3–4 days.

How long does a stool culture take to yield final results?