15.1 Laboratory Equipment Maintenance

15.1 Laboratory Equipment Maintenance

Quick Answer: The MLA keeps basic equipment clean, balanced, logged, and within temperature limits. Do daily care on pipettes, centrifuges, and microscopes—never adjust calibration without authorization. Monitor refrigerators, freezers, and incubators; act immediately on out-of-range temps. Never store personal food with reagents or specimens. Tag broken equipment out of service until released per policy.

Equipment maintenance sits in Domain IV: Laboratory Operations on the ASCP MLA content guideline for testing dates beginning June 1, 2026 (outline letters covering equipment care alongside ethics, LIS, and quality). Entry-level assistants are not biomedical engineers, but they are the people who notice a wet centrifuge bowl, a warm reagent fridge, or a fogged microscope objective before those problems become wrong results or discarded specimens.

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Scope: User Care vs Authorized Calibration

Rule of thumb: if the action changes how an instrument measures (volume, speed, temperature accuracy, optical alignment beyond simple cleaning), stop and escalate to a supervisor, biomedical engineering, or the vendor. Unauthorized calibration is both a quality failure and often a policy violation.

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Pipettes

Pipettes (manual and electronic) transfer precise liquid volumes for reagents, QC, aliquots, and waived testing support.

Daily / use-level care

• Inspect shafts, seals, and tips for cracks, looseness, or dried residue.
• Use correct tips for the pipette model; poorly seating tips cause volume error and splash risk.
• Never lay a pipette with liquid in the tip horizontally—fluid can enter the piston chamber.
• Wipe exteriors with approved disinfectant after use or contamination; avoid soaking unapproved parts.
• Hang or stand pipettes upright in racks when not in use.
• Report sticky plungers, inconsistent aspiration, or damaged noses—do not keep using a “pretty close” pipette for patient-related volumes.

Calibration awareness

Facilities schedule periodic verification/calibration (often quarterly or per manufacturer and accreditation plan). The MLA may deliver pipettes to the calibration program and document receipt of certificates—but must not turn calibration screws or change software volume offsets unless that exact task is in their validated competency and SOP. Exam trap: “The volume looks low, so I adjusted the dial until water weight seemed right.” That is unauthorized calibration.

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Centrifuges

Centrifuges separate cells from plasma/serum, prepare urine sediments, and support processing workflows (see also centrifugation technique in Domain II processing chapters).

Balance and load

1. Load equal volumes / equal mass opposite each other (use balance tubes with water when needed).
2. Confirm correct rotor and adapters for tube size; wrong adapters can crack tubes.
3. Close the lid fully; never override interlocks.
4. Select approved RCF/time from SOP—not a remembered “standard spin” for every tube type.
5. Wait for full stop before opening; do not brake with hands on the rotor.

Cleaning and spills

• Clean bowls, buckets, and adapters on the schedule (often daily or after each shift for high-use units) and immediately after spills.
• Treat blood/body fluid spills as biohazard events: PPE, approved disinfectant with correct contact time, and documentation if required.
• Inspect for corrosion, cracks, and loose trunnions.
• Never centrifuge uncapped specimens unless SOP specifically allows sealed rotors designed for that purpose—aerosol risk is real.

Maintenance logs

Record cleaning, brush inspections (if required), outages, unusual noise/vibration, and service visits. Accreditation surveyors and internal QA programs look for complete logs. An empty log after a week of heavy use is itself a finding.

Out of service

If a centrifuge vibrates excessively, will not reach speed, smells of burning, or fails safety checks, power down if safe, tag out of service, move work to a backup unit, and notify leadership. Do not “finish this one STAT rack” on a failing instrument.

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Microscopes

MLAs support smear review areas, urine sediment stations, and teaching scopes even when licensed staff perform final interpretation.

Report stuck focus knobs, stage drift, or missing eyepieces. Do not force frozen mechanisms with tools.

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Balances and Glassware

Analytical / top-loading balances

• Level the balance; zero/tare before use.
• Keep the weighing chamber clean and free of powder spills.
• Use weigh boats or paper as required; do not pour corrosive reagents directly on the pan.
• Protect from drafts and vibration; close draft shields when specified.
• Know that calibration weights and service schedules are controlled—do not invent check weights from random objects.

Glassware and plasticware

• Inspect for chips, cracks, and etched volume marks—damaged volumetric ware is unsafe and inaccurate.
• Wash and dry per lab protocol; residual detergent interferes with some assays.
• Store clean glassware protected from dust; do not use scratched disposable cuvettes as “permanent” glassware.
• Match Class A volumetric requirements when the SOP specifies them; random beakers are not volumetric flasks.

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Environmental Equipment: Cold Storage, Incubators, Thermometers

Refrigerators and freezers

Laboratory cold units store reagents, controls, kits, and sometimes specimens. Requirements typically include:

• Continuous or scheduled temperature monitoring (chart recorders, digital probes, or manual logs per policy)
• Defined acceptable ranges (e.g., refrigerator ~2–8 °C for many reagents—always use the product and SOP range)
• Alarm response when available (do not silence alarms and walk away)
• Inventory organization so doors are not left open; frost buildup reported
• Separate clinical units from break-room appliances

Incubators

Microbiology and some specialty areas use incubators at set temperatures (e.g., 35–37 °C). MLAs who support plating/setup must:

• Verify displayed and logged temperature at required intervals
• Avoid prolonged door opening
• Report temperature excursions before incubating critical cultures if the unit is out of range
• Clean spills and maintain humidity pans only as SOP directs

Thermometers and NIST-traceable awareness

Facilities use thermometers that are calibrated or verified against standards traceable to NIST (or equivalent national metrology institutes). The MLA does not need to recite NIST history, but must:

• Use only designated monitoring thermometers/probes for logs—not a random kitchen thermometer from home
• Place probes in glycerin bottles or approved media when the SOP requires buffered readings (avoids door-open spikes)
• Respect calibration due dates on stickers/certificates; remove expired devices from monitoring duty
• Record temperatures at the required times (often opening of business, mid-shift, and closing—or continuous electronic monitoring)

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Out-of-Range Temperature Response

When a refrigerator, freezer, or incubator is outside the acceptable range:

1. Confirm the reading (second thermometer if policy allows; check probe placement; ensure door is closed).
2. Do not ignore a single “almost OK” reading if the unit is still drifting or alarming.
3. Protect contents: move critical reagents/specimens to a qualified backup unit if directed; do not leave temperature-sensitive kits in a warming fridge “until maintenance arrives.”
4. Notify the supervisor, charge tech, or on-call designee promptly.
5. Document time discovered, readings, actions, who was notified, and disposition of affected materials.
6. Participate in impact assessment (what lots were stored, whether QC or patient testing is affected)—leadership decides discard vs quarantine vs continued use with investigation.
7. Resume normal use only when the unit is stable in range and released per policy.

Exam judgment: discovering a freezer at −5 °C when it should be −20 °C and continuing to restock frozen controls without notification is a critical failure.

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Personal Food Ban in Lab Storage

Never store personal food or drinks in refrigerators or freezers that hold reagents, specimens, blood products, or microbiology media. Reasons:

• Cross-contamination and ingestion risk (bloodborne pathogens, chemicals)
• Regulatory and accreditation standards separate staff food from laboratory materials
• Odors, spills, and overcrowding compromise sample and reagent integrity
• Appearance of unprofessional and unsafe practice during surveys and patient tours

Staff food belongs in designated break-room appliances only. Likewise, do not use the lab microwave for lunches if it is designated for laboratory procedures.

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Documentation Culture

Maintenance is only as good as the record that proves it happened:

• Complete logs the same day—do not backfill a week of temperatures from memory before inspection
• Use legible initials, correct units (°C vs °F), and real times
• File service tickets and calibration certificates where the QA plan expects them
• Communicate recurring problems (fridge that drifts every afternoon) so engineering can fix root causes

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Connecting Equipment Care to Patient Results

/practice/ascp-mlaPractice questions with detailed explanations

Related study guide sections: centrifugation and processing (Chapter 8), reagents and instrument QC (Chapter 10), chemical and fire safety (Chapter 13), and infection control (Chapter 14).