7.2 Cultures, Smears, Labeling & Documentation

Cultures and Smears in the CMAC Specimens Domain

Blueprint tasks 3.03.16 (obtain cultures and smears), 3.03.17 (label specimens), and 3.03.18 (document procedures) turn a “simple swab” into a regulated diagnostic process. Contaminated blood cultures drive unnecessary antibiotics and hospitalizations. Mislabelled wound swabs can assign MRSA to the wrong patient. Learn each common specimen type, then apply one non-negotiable labeling and documentation standard to all of them.

3.03.16 Obtain Cultures and Smears

Blood cultures

Blood cultures detect bacteremia/fungemia. Contamination with skin flora (e.g., coagulase-negative staphylococci) creates false positives.

Exam traps: drawing cultures last “after the CBC”; prepping with a single alcohol swipe; collecting only a few drops; labeling bottles in the lab hallway after leaving the room.

Sputum cultures

Sputum evaluates lower respiratory pathogens. Saliva is not sputum.

1. Preferably collect first-morning specimen after rinsing mouth with water (no mouthwash that kills organisms if lab prohibits).
2. Instruct deep cough from the chest into a sterile cup—not throat-clear spit.
3. Expect thick, mucoid material; watery clear saliva is inadequate—recollect.
4. Cap, label, bag, send promptly; refrigerate if delay per lab for some tests (follow SOP).
5. For AFB/TB suspects, follow airborne precautions and facility collection booth/isolation rules—scope and PPE matter.

Nasal and nasopharyngeal specimens

Used for MRSA screening (anterior nares) and many viral PCR panels (NP swab).

Anterior nares (e.g., MRSA screen):

• Insert swab into nostril and rotate against mucosa per kit (often both nares with same swab if directed).
• Avoid touching skin outside the naris excessively.
• Place swab into transport medium; break shaft if designed to.

Nasopharyngeal (NP):

• Patient head slightly tilted; insert flexible swab along floor of nose to nasopharynx until resistance.
• Rotate gently, withdraw, place in medium.
• Warn of brief discomfort/tearing/sneeze.
• Wrong depth (only tip of nose) → false negatives on viral tests.

Throat cultures / rapid strep swabs

1. Good light; depress tongue gently.
2. Swab both tonsillar pillars and posterior pharynx; include exudate if present.
3. Avoid tongue, teeth, and cheeks—oral flora contaminates interpretation for culture and may affect some assays.
4. For dual testing (rapid + culture backup), follow kit: sometimes two swabs or specific order.

Wound cultures and smears

Never culture through intact contaminated dressings without cleaning. Document if the wound was irrigated before sampling.

Other ambulatory cultures (awareness)

• Eye/ear: specialized swabs; avoid contamination from adjacent skin.
• Vaginal/cervical: often provider-collected; MA may assist with supplies, lighting, labeling.
• Stool culture/ova & parasite: correct vials (Cary-Blair, PVA/formalin), patient instruction, no urine contamination in stool cup.

Smears in the MA role

Depending on state law and training, MAs may prepare or assist with:

• Wound smears for lab Gram stain
• Wet mounts (e.g., vaginal) under supervision/protocol
• Blood smears in some settings (more lab tech territory)

Rules that always apply: correct patient label on slide frosted end in pencil if required, site noted, biohazard handling, no bare-hand contact with specimen side.

3.03.17 Label Specimens Correctly

Wrong-patient labeling is a never event class error.

Minimum label elements (typical)

Labeling best practices

1. Label at the bedside or side-by-side with the patient after collection—not in a batch room later.
2. Place label on the container body, not only the lid (lids get swapped).
3. Do not pre-label multiple empty tubes/cups for a queue of patients before collection.
4. Verify label against armband/stated ID and requisition before bagging.
5. For computer labels, still read the name—printer errors happen.
6. Aliquots and slides get their own labels matching the primary specimen.
7. If a label is wrong, follow lab recollection policy—do not peel and restick casually if chain of identity is broken.

Special labeling situations

3.03.18 Document Procedures

If it is not documented, the care team cannot interpret delays, contamination risk, or who to contact for recollection.

What to document

• Patient ID verification method
• Procedure performed (e.g., “blood culture ×2 sets, R AC and L AC”)
• Site(s) and laterality
• Time of collection (and time sent if different)
• Number/type of bottles, swabs, or containers
• Skin prep used for blood cultures
• Patient tolerance, complications (dizziness, bleeding, refusal)
• Who collected and who notified if problems
• Teaching provided (sputum technique, urine CCMS)
• Chain-of-custody form numbers when applicable

Documentation quality examples

Weak: “Labs done.”
Strong: “Blood cultures: 2 sets obtained from right antecubital and left antecubital after CHG prep dried fully. Aerobic/anaerobic bottles filled to fill lines. Labeled at bedside. Patient tolerated well. Specimens to lab at 09:40 via pneumatic tube.”

Weak: “Wound swab.”
Strong: “Aerobic wound culture swab from base of left plantar ulcer after saline cleansing of surface debris; labeled site-specific; patient reports mild tenderness.”

Legal and quality angle

Documentation supports:

• Clinical interpretation (e.g., antibiotics started before culture?)
• Infection prevention review of contamination rates
• Liability defense if a patient alleges wrong-site or wrong-person testing
• Billing/medical necessity trails when required

Never document a collection you did not perform. Never alter times to hide delays—correct with late-entry notation per policy.

Putting Culture + Label + Document Together

flowchart TD
    A[Verify order and patient ID] --> B[Collect with site-specific aseptic technique]
    B --> C[Label container at point of collection]
    C --> D[Bag bag and transport per specimen rules]
    D --> E[Document procedure site time collector]
    E --> F[Communicate issues to provider or lab]

High-Yield Error Table

Role Boundaries

Perform only collections within CMAC scope, training, and facility privilege. Invasive procedures (e.g., some catheterizations, lumbar CSF) belong to licensed clinicians. Your consistent excellence is in technique you are trained for, perfect labeling, and complete documentation—the three tasks this section maps to the blueprint.

Master blood-culture prep, sputum vs saliva, NP depth, throat landmarks, and wound-base sampling. Then treat every container as if a second patient with the same name is sitting in the next chair—because someday they will be.