Chapter 18 Condensed


Chapter 18 — Collecting Specimens

Condensed Study Guide

Core specimen rules

For all specimen collection:

  • Verify the prescribed test.

  • Identify the patient.

  • Explain the procedure.

  • Perform hand hygiene.

  • Use gloves/PPE as indicated.

  • Prevent contamination.

  • Label correctly.

  • Place in biohazard bag when indicated.

  • Transport promptly.

  • Document collection method, specimen characteristics, patient findings, and transport/results as appropriate.

Standard Precautions

Use Standard Precautions whenever exposure to blood/body fluids or secretions may occur.

Key actions:

  • Hand hygiene before/after.

  • Gloves for urine, stool, sputum, wound drainage, etc.

  • Additional PPE based on exposure risk.

  • Avoid contaminating specimen/container.

  • Dispose of contaminated items correctly.

  • Transport specimens in appropriate biohazard packaging.


Urine Characteristics

Normal findings

  • Color: pale yellow, straw, or amber.

  • Odor: aromatic.

  • Turbidity: clear/translucent when fresh.

  • pH: about 6.0

  • pH range: 4.6–8

  • Specific gravity: 1.015–1.025

Important findings

  • Dark urine = more concentrated.

  • Light urine = more dilute.

  • Fresh cloudy urine = abnormal.

  • Sweet odor may occur with glucose.

  • Fetid odor may occur with infection.

  • Higher specific gravity may indicate dehydration.

  • Lower specific gravity may indicate overhydration.

Abnormal urine constituents

  • Pus

  • Albumin

  • Glucose

  • Ketone bodies

  • Casts

  • Gross bacteria

  • Bile


Clean-Catch Midstream Urine

Purpose

Collect fresh urine while reducing contamination from surrounding skin/anatomical structures.

Female technique

  • Separate labia.

  • Clean each side of meatus.

  • Clean center.

  • Clean front to back.

  • Use a new wipe/clean area for each stroke.

  • Keep labia separated during collection.

Male technique

  • Clean around meatus in a circular motion away from urethra.

  • If uncircumcised:

    • retract foreskin,

    • cleanse and collect,

    • replace foreskin afterward.

Collection

  1. Begin voiding into toilet/bedpan/commode.

  2. Briefly interrupt.

  3. Collect midstream urine.

  4. Obtain at least 3–5 mL.

  5. Finish voiding normally.

Never

  • Touch inside of cup or lid.

  • Let cup touch skin or hair.

  • Allow stool or toilet paper into specimen.

Transport

Send to lab ASAP.

If delayed:

  • Refrigerate according to instructions.

  • Textbook notes urine may be refrigerated up to 24 hr.

Key memory

Clean → start void → catch middle → finish void


Urine From an Indwelling Catheter

Most important rule

Sample from the PORT — NEVER the BAG

Do not disconnect the drainage system to collect urine.

Procedure

  1. Verify order.

  2. Hand hygiene/PPE.

  3. Identify patient.

  4. Clamp/bend tubing distal to sampling port.

  5. Clamp at least about 3 inches below port.

  6. If necessary, allow urine to collect for up to 30 min.

  7. Scrub aspiration port vigorously with alcohol/antimicrobial wipe.

  8. Allow port to air dry.

  9. Aspirate at least 3–5 mL.

  10. Remove syringe.

  11. Unclamp tubing immediately.

  12. Transfer urine slowly into specimen container.

  13. Label, bag, transport.

Why unclamp promptly?

Prevents bladder overdistention/injury.

Memory

Clamp → Scrub → Dry → Aspirate → Unclamp


Stool for Occult Blood — Hemoccult/gFOBT

Purpose

Detect occult blood in stool.

gFOBT detects peroxidase activity associated with hemoglobin.

Collection precautions

Do not contaminate stool with:

  • urine,

  • toilet paper.

Hemoccult procedure

  1. Open sample flap.

  2. Take stool from center of bowel movement.

  3. Apply to first window.

  4. Use opposite end of applicator.

  5. Take stool from a second area.

  6. Apply to second window.

  7. Close flap.

  8. Wait 3–5 minutes.

  9. Open developer side.

  10. Apply 2 drops of developer to each window.

  11. Observe result.

Positive result

BLUE = BLOOD = POSITIVE

gFOBT may require 3–6 different stool samples.


FIT

FIT uses antibodies against human hemoglobin.

Results

  • Pink T line = positive

  • No pink C/control line = invalid

If control line is absent:

  • do not report result,

  • repeat test with new device.

FIT generally uses fewer specimens than gFOBT.


General Stool Specimen

Usual amount

  • 1 inch / 2.5 cm formed stool
    OR

  • 30 mL liquid stool

If visible:

  • blood,

  • mucus,

  • pus,

include those portions.

Prevent contamination

  • Patient should void first.

  • Do not include urine.

  • Do not include toilet paper.

  • Avoid menstrual blood contamination.

Transport

Send while specimen is fresh/warm when appropriate.

Important:

Do NOT refrigerate specimens for ova and parasites.


Normal Stool Characteristics

Color

  • Infant: yellow to brown.

  • Adult: brown.

Important color clues

  • Black: may occur with upper GI bleeding, iron, some antacids.

  • Fresh blood: may reflect lower intestinal bleeding.

  • White/clay: may occur with absence of bile.

Odor

Normally pungent.

Consistency

  • soft,

  • semisolid,

  • formed.

Shape

About 1 inch / 2.5 cm diameter.

Pencil-shaped stool may be associated with obstruction.


Sputum Collection

A true sputum specimen comes from the:

Lower respiratory tract

Saliva is NOT an acceptable sputum specimen.

Procedure

  • Preferably collect first thing in the morning.

  • Place patient in semi-Fowler position.

  • Have patient clear nose/throat.

  • Rinse mouth with water.

  • Take 2–3 deep breaths.

  • Cough forcefully.

  • Expectorate into sterile container.

Usually:

1–3 mL

is sufficient.

Transport

Send immediately.

If specimen has sat at bedside and collection time is unknown:

  • discard,

  • recollect.


Nasal Swab

  • Insert approximately 1.5 cm into nostril.

  • Rotate against anterior nasal mucosa at least 4 times for ~15 sec.

  • Repeat in second nostril using same swab.

  • Avoid contaminating swab.

  • If swab touches another surface:

    • discard,

    • use new swab.


Nasopharyngeal Swab

  • Patient blows nose first.

  • Tilt head back.

  • Insert swab straight back, not upward.

  • Follow floor of nasal cavity.

  • Adult insertion approximately 9–10 cm.

  • Do not force.

  • Rotate and leave briefly.

  • Remove without touching sides.

If obstruction occurs:

  • do not force,

  • try other nostril.


Documentation

Document the applicable:

  • specimen type,

  • collection method,

  • date/time,

  • appearance/characteristics,

  • relevant symptoms,

  • patient tolerance,

  • test/result if nurse performs testing,

  • transport to laboratory,

  • education provided.

Urine

Document:

  • color,

  • clarity,

  • odor,

  • amount if known,

  • dysuria or other symptoms,

  • collection method.

Stool

Document:

  • amount,

  • color,

  • consistency,

  • collection time,

  • test ordered,

  • transport.

Respiratory specimens

Document:

  • collection time,

  • relevant assessment findings,

  • specimen characteristics,

  • transport.


Must-Know Numbers

Topic

Number

Urine pH

~6.0

Urine pH range

4.6–8

Specific gravity

1.015–1.025

Clean-catch urine

≥3–5 mL

Catheter urine

≥3–5 mL

Catheter clamp time

up to 30 min

Formed stool

1 in / 2.5 cm

Liquid stool

30 mL

Hemoccult wait

3–5 min

Hemoccult developer

2 drops/window

gFOBT samples

3–6

Nasal swab depth

1.5 cm

Nasopharyngeal depth

9–10 cm adult

Sputum

1–3 mL

Highest-Yield Memory Rules

Clean catch:
Clean → void → MIDSTREAM → cup → finish

Catheter urine:
PORT, NEVER BAG

Catheter port:
Clamp → scrub → AIR DRY → aspirate → unclamp

Hemoccult:
2 stool areas → 2 windows → 2 drops/window → BLUE = positive

FIT:
T pink = positive; no C = invalid

Stool:
No urine. No toilet paper.

Sputum:
From lungs, not saliva.

Specimens overall:
Correct patient + uncontaminated sample + correct label + prompt transport + documentation