# Pipetting Training Documentation: What to Record Pipetting training documentation is the written record that proves a trainee can handle liquid transfers accurately, reproducibly, and with correct technique before they work unsupervised on real samples. The document captures who was trained, on which pipette and tip lot, against which performance standard, and what objective measurements showed. A well-built record does three jobs at once. It demonstrates competency for quality systems and audits, it identifies the specific technique errors a trainee needs to correct, and it protects downstream experiments by tying every future data set back to a verified skill. Use this documentation process whenever a new student, technician, or visiting researcher joins a lab, whenever someone moves to a new pipette type such as a multichannel or positive displacement instrument, and after any event that could degrade skill or equipment, such as a long absence, a pipette drop, or a repair. Most quality systems treat pipetting as a trained, documented competency because nearly every [molecular biology](/blog/careers/molecular-biology) assay, from plasmid prep to qPCR, inherits its accuracy from the pipette. The hands-on time is modest. A single training session with a gravimetric check takes about 2 to 3 hours per trainee per pipette class, including setup, the measurement series, calculations, and the feedback discussion. Elapsed time from first session to signed competency is usually 3 to 7 days, because the record should include a short practice interval, a repeat check, and countersignature by the trainer. Plan the schedule before the trainee picks up a pipette so the documentation is complete rather than reconstructed afterward. This article walks through the principle behind the documentation, a step-by-step procedure, the exact fields to record, how to run and interpret the gravimetric check that anchors the record, common mistakes, and answers to the questions trainees and supervisors ask most often. ## Materials and Setup Gather everything before the session. Interrupting a measurement series to hunt for a balance check weight or a fresh tip box undermines the record, because environmental exposure time and pipetting rhythm change between interrupted and uninterrupted runs. | Item | Specification or working condition | Purpose | |--|--|--| | Air displacement pipettes | Single channel covering the volume range the trainee will use, for example 2 to 20 µL, 20 to 200 µL, and 100 to 1000 µL | The instruments being certified | | Compatible tips | One lot, from the brand validated for that pipette, enough for practice plus the check series | Tip fit and wetting behavior affect volume delivery | | Type I or distilled water | Equilibrated to room temperature, 20 to 25 °C, with a bottle on the bench for at least 1 hour | The test liquid for the gravimetric check | | Analytical balance | Readability of 0.1 mg for volumes of 100 µL and above, 0.01 mg for smaller volumes, with draft shield and level bubble | Measures dispensed water mass | | Certified check weight | Mass traceable to a national standard, near the expected dispensed mass | Daily verification that the balance itself is sound | | Weighing vessel | Small glass or metal vessel, or a dedicated evaporation trap insert, containing a few millimeters of water | Prevents evaporation loss during weighing | | Pipetting training record form | Paper or electronic template with all fields listed below | The documentation itself | | Timer | Any bench timer or phone | Standardizes pause times during technique | | PPE | Lab coat, safety glasses, gloves | Standard bench protection | | Training solutions (optional) | Water with a small amount of nonhazardous dye or glycerol solution for visual feedback drills | Helps trainees see aspirate and dispense behavior | Safety note. Water and dilute dyes used for training are low hazard, but standard PPE is still required because training happens on the open bench. Never use clinical samples, cultures, or any biohazardous material as training liquid. Mouth pipetting is prohibited in every setting, and the training record itself should show that the trainee was instructed in mechanical pipette use only. ## Principle: Why Documentation and Gravimetric Checks Work Pipetting accuracy depends on two things the record must capture separately. The first is the instrument. A pipette that is out of calibration will deliver wrong volumes no matter how skilled the operator is. The second is the operator. A trainee with poor technique, such as releasing the plunger too fast or dipping the tip too deep, will deliver inconsistent volumes even with a perfectly calibrated pipette. Pipetting training documentation separates these variables in a specific order. The pipette is first confirmed to be within its calibration interval and, ideally, verified gravimetrically on the day of training by the trainer or by a reference operator. Then the trainee performs the same gravimetric check, and the resulting precision reflects the trainee rather than the instrument. If the pipette calibration status is not recorded and verified first, a poor trainee result is ambiguous, and the record loses its diagnostic value. The gravimetric check itself is simple physics. Water is dispensed into a weighing vessel on an analytical balance, the delivered mass is recorded, and mass is converted to volume using the density of water at the test temperature. At 20 °C the density of water is approximately 0.99821 g/mL, so a mass of 99.82 mg corresponds to a delivered volume of 100.0 µL. Because 1 µL of water weighs close to 1 mg, the balance reading is nearly the volume, with a small temperature correction. Repeating the delivery ten times at each test volume gives a mean (systematic error, how far off target the operator plus instrument are on average) and a standard deviation (random error, how scattered the deliveries are). Those two numbers, usually expressed as a percent of the nominal volume and as a [coefficient of variation](/blog/research-skills/how-to-calculate-coefficient-of-variation), are the core performance data in the record. This gravimetric approach is the method recommended by pipette manufacturers in their technical documentation and is structured in industry standards such as ISO 8655, which specifies replicate deliveries at defined points across the pipette's volume range. The training record borrows that structure at trainee scale. ## What a Pipetting Training Record Contains A complete record has six blocks of fields. Missing any one of them weakens the document, usually at audit time or when a troubleshooting investigation later needs to trace a performance problem to its source. ### Trainee and Trainer Identifiers Record the trainee's full name and employee or student identifier, the trainer or assessor's name, the date of each session, the laboratory or room where training occurred, and the protocol or standard operating procedure version the training followed. Include the trainee's prior experience level, stated simply, for example "no prior pipetting experience" or "experienced with single channel, new to multichannel." This field matters because interpretation of results depends on expectations. A coefficient of variation of 2 percent from a first-day beginner calls for coaching, while the same number from someone claiming years of experience calls for a different conversation. Record the signatures of both parties. An unsigned training record is a draft, not a competency document. In electronic systems, capture the electronic signature event rather than a typed name. ### Pipette and Tip Information Record the pipette manufacturer, model, nominal volume range, serial number or asset tag, and the channel count. Record the tip brand, tip type (standard, low retention, filtered), and the tip lot number. Tip lot matters more than most trainees expect. Orifice geometry and hydrophobic treatment differ between lots, and a pipette verified with one lot may behave slightly differently with another. If the lab later switches tip lots, the record explains why a recheck may be needed. Also record the pipette's condition notes, such as "externally verified within the last month," "seal replaced," or "dropped and returned to service after recalibration." These notes are the bridge between the training record and the instrument maintenance history. ### Pipette Calibration Status Record the last calibration date, the calibration due date, who performed the calibration (external service or in-house), and whether a certificate or in-house verification record is on file with its document number. State explicitly whether the pipette passed its own check on or near the training date. This is the field that makes the training record defensible, because it ties trainee performance to an instrument of known accuracy. A training session performed with an overdue pipette should be documented as such, and the competency decision should be deferred until a calibrated instrument is available. Calibration intervals are set by institutional policy and manufacturer guidance, and most labs use 6 to 12 months for pipettes in daily use. Regardless of the interval, the record should note that any drop, immersion of the shaft, or physical damage triggers an immediate verification, and that event should appear in the instrument history with a date. ### Gravimetric Check Data ![Calculation converting a mean delivered mass of 499.5 mg of water at 20 °C into a volume of 500.6 µL, with standard deviation and systematic error.](/article-images/illustrations/pipetting-training-documentation-gravimetric-worked-example.webp) This is the numerical heart of the record. For each test volume, typically 100 percent and 10 percent of the pipette's nominal maximum, record all ten individual mass readings in milligrams, not just the summary statistics. Individual readings let a reviewer distinguish between one wild outlier and a uniformly scattered series, which point to different problems. Then record the derived values for each volume: mean delivered mass, mean delivered volume after temperature correction, standard deviation, coefficient of variation, and systematic error as a percent of the nominal volume. Record the water temperature at the time of the check and the balance identification with its check weight result for that day. A concrete worked example makes the expectations clear. A trainee sets a 100 to 1000 µL pipette to 500 µL and delivers water ten times onto the balance. The readings cluster between 497.6 and 502.1 mg. The mean mass is 499.5 mg. With water at 20 °C, the mean volume is 499.5 mg divided by 0.99821 mg/µL, which is 500.6 µL. The standard deviation of the ten readings is 1.3 mg, so the coefficient of variation is about 0.26 percent. The systematic error is 500.6 µL against a nominal 500 µL, which is 0.12 percent high. Whether that passes depends on the manufacturer's specification for that model at that volume and on the lab's trainee thresholds, and both of those references are recorded alongside the numbers. ### Technique Checklist Results Numbers alone do not tell you how to fix a problem, so the record includes a scored checklist of the observable elements of good pipetting technique. Score each element as performed correctly, performed with correction needed, or not yet assessed. The checklist items covered in detail in the technique section below include tip insertion, pre-rinsing, plunger control, immersion depth and angle, dispense method, and post-dispense handling. Include space for written observations, because they are the most useful part of the record during retraining. "Consistently releases the plunger too fast on the 10 percent volume, causing underdelivery and bubbles" is worth more to the next training session than any single number. ### Pass, Fail, and Remediation Decisions Record the explicit decision: competent, competent with restrictions (for example "cleared for volumes above 50 µL only"), or not yet competent, along with the specific criteria used. Record the agreed remediation plan if the result is not a pass, with a scheduled reassessment date. Record the date on which unsupervised work is authorized, and who authorized it. Finally, record the reassessment schedule, since competency is not a lifetime award. Many labs re-assess annually, after extended absence, or when the trainee moves to a new pipette class or a new assay type. ## Pipetting Training Documentation Step by Step The following procedure covers pipetting training documentation step by step, from bench preparation to countersigned record. Record information as you go rather than afterward. Memory-based reconstruction is the single largest source of documentation gaps. 1. **Verify the pipette's calibration status and record it.** Check the calibration sticker or asset database for the last and due dates, and record both on the training form with the certificate or in-house verification reference. Reason: the trainee assessment is only interpretable if the instrument is known to be accurate. If the pipette is overdue, stop and use a calibrated pipette instead. 2. **Verify the balance with a certified check weight and record the result.** Place the check weight on the balance, confirm the reading is within the weight's tolerance, and write the check weight identifier, nominal mass, observed reading, and time on the form. Reason: the balance is the measuring instrument for the entire competency check, and a daily check weight log is standard laboratory practice. An unverified balance invalidates every number that follows. 3. **Record the environmental conditions.** Write the ambient temperature and, if available, the relative humidity. Allow the water bottle and pipettes to sit on the bench until they reach room temperature, at least 1 hour, and note the equilibration time. Reason: water density changes with temperature, and a cold bottle of water pipetted immediately creates a systematic volume error and condensation on the tip that disrupts delivery. 4. **Record the pipette model, serial number, tip brand, and tip lot.** Do this before the first aspiration. Reason: tip lot and pipette identity are the reference points for any future comparison, and a session recorded against the wrong tip lot cannot be compared to later checks. 5. **Demonstrate the technique while narrating each element.** The trainer performs five to ten slow, deliberate aspirate and dispense cycles at mid-range volume, verbalizing plunger positions, tip depth, and timing. The trainee watches without pipetting. Reason: observational learning before hands-on practice reduces the number of embedded errors the record will later have to catch, and the narration establishes the shared vocabulary used in the checklist. 6. **Supervised practice, undocumented as performance but documented as a session event.** The trainee practices for 20 to 30 minutes while the trainer corrects grip, angle, and plunger speed. Record that practice occurred, its duration, and the corrections given. Reason: practice data are not competency data, and mixing them confuses the record. The corrections given, however, become the baseline for the checklist comparison later. 7. **Perform the training check at 100 percent of nominal volume.** The trainee performs ten replicate deliveries onto the balance while the trainer scores the technique checklist silently. The trainee pre-rinses the tip two to three times before the series, aspirates with the plunger pressed to the first stop, pauses about 1 second at full immersion, dispenses against the vessel wall at a consistent angle, and pauses about 1 second before withdrawing the tip. Record all ten mass readings immediately, in order, with any anomalies noted, such as a bubble clinging to the orifice or a splash outside the vessel. Reason: sequential recording preserves the ability to detect drift, which often appears as a first reading that differs from the rest because the tip was not pre-rinsed. 8. **Repeat the check at 10 percent of nominal volume.** Change to a fresh tip, pre-rinse, and deliver ten replicates. Record the readings and note the checklist scores, which frequently differ from the high volume because small volume technique is less forgiving of slow release and shallow immersion. Reason: pipettes are least accurate near the bottom of their range, and this is where trainee technique differences show most clearly. Avoid setting the volume near the very bottom of the pipette's adjustable range in routine work for the same reason. 9. **Calculate the summary statistics while the trainee waits or participates.** Compute the mean, standard deviation, coefficient of variation, and systematic error for each volume, convert mass to volume with the temperature-corrected density, and write the values on the form. Show the trainee the arithmetic. Reason: trainees who understand the calculation connect the physical actions to the numbers, which accelerates correction. A trainee who sees that five erratic readings at low volume drove the coefficient of variation from 0.5 to 2 percent understands exactly which habit to fix. 10. **Compare results to the pass criteria and record the decision.** The criteria have two layers. The instrument layer is the manufacturer's stated accuracy and precision specification for that model at the tested volumes. The trainee layer is the lab's defined competency threshold, which is typically set at or slightly above the manufacturer's random error specification to allow for human variation. Record both the numbers and the criteria on the form. Reason: a pass without a stated criterion is an opinion. A pass against a written criterion is a competency determination. 11. **Complete the technique checklist and write the feedback summary.** For each checklist element, mark correct, needs correction, or not assessed, and write two or three specific sentences of feedback with the planned corrections. Reason: this section drives the next session, and vague entries such as "good overall" provide nothing to retrain against. 12. **Sign, date, and countersign the record, then file it.** The trainee signs to confirm the training occurred and the feedback was received. The trainer signs to confirm the assessment. File the record in the training binder or the electronic training management system the same day, and record the reassessment due date in the lab's tracking system. Reason: the value of the document depends on its retrievability, and same-day filing prevents the most common audit finding, which is a completed but unfiled record. ## The Pipetting Technique Being Assessed The checklist items in the record map directly onto the elements of sound pipetting technique. Documenting them requires knowing what correct looks like and why each element exists. **Tip insertion.** Press the tip onto the shaft with a slight twist until you feel or hear a seal. A partially seated tip leaks air and underdelivers. Record observations about insertion force and visible gaps. **Pre-rinsing.** Aspirate and dispense the working volume two to three times into the source vessel before the measured series. Pre-rinsing equilibrates the residual liquid film inside the tip, which reduces evaporation loss during the brief pause in the tip and improves delivery consistency, especially for small volumes and volatile solutions. Record whether pre-rinsing was done, because skipping it often explains a first-reading outlier. **Immersion depth and angle.** Immerse the tip only 2 to 3 mm below the liquid surface for small volumes, and a few millimeters deeper for larger ones, holding the pipette vertical during aspiration. Too deep and liquid clings to the outside of the tip and gets carried into the delivery. Too shallow and the tip can pull in air at the surface. A tilted pipette changes the hydrostatic pressure at the orifice and systematically alters the aspirated volume. Both errors are visible and both belong on the checklist. **Plunger control.** Press to the first stop before immersion, aspirate smoothly and steadily, and release the plunger slowly and consistently. Fast release pulls liquid at high velocity, creates bubbles and aerosol, and leaves less liquid in the tip than the calibration assumed. Fast, inconsistent release is the most common single cause of poor precision in trainees, which is why the record should describe it whenever observed. **Dispensing.** Touch the tip to the side wall of the receiving vessel at a consistent angle, press steadily through the first stop and then to the second stop (the blow-out stroke) to expel the residual film, and hold about 1 second before withdrawing. For viscous or foaming liquids, the trainer should introduce reverse pipetting, in which the plunger is pressed to the second stop for aspiration and only to the first stop for dispensing, leaving excess in the tip. Record which mode was used, because the mode changes the delivered volume and the two modes cannot be compared in the same data series. **Post-dispense handling.** Eject the tip into a sharps or waste container using the ejector button, never by pulling it off by hand. Record whether the trainee ejects contaminated tips safely, because this is a biosafety element of competency, not just a performance one. ## Controls and Environmental Conditions Three controls make the training record trustworthy, and each has its own line on the form. The **instrument control** is the pipette calibration status discussed above. For labs that want maximum rigor, the trainer or a designated reference operator performs the same ten-replicate gravimetric series with the same pipette and tips before the trainee begins. That reference series, recorded on the form, isolates instrument performance from trainee performance in a way a calibration date alone does not. The **balance control** is the daily check weight measurement, recorded with its observed value. Balance readings also drift with static electricity and drafts, so the form should include a box confirming that the draft shield was closed during readings and that the operator waited for a stable reading before recording. The **environmental control** is the recorded room temperature, which supplies the water density used in the mass-to-volume conversion. As a working rule, using the 20 °C density value when the bench is actually at 25 °C introduces a systematic error of roughly 0.2 to 0.3 percent, which is the same order as the performance differences you are trying to measure. Record the actual temperature and use the matching density. ## Expected Results and How to Read Them ![Triage of gravimetric result patterns: first reading outlier, steady drift, good at high volume but poor at low volume, and scattered readings.](/article-images/illustrations/pipetting-training-documentation-reading-the-data.webp) Read the record in two dimensions: how close the mean is to the target (accuracy) and how tight the replicates are (precision). A trainee can be precise but biased, which usually indicates a technique habit such as inconsistent immersion depth, or accurate on average but scattered, which usually indicates inconsistent plunger speed or timing. Use the following interpretation guide, with the understanding that specific numeric thresholds come from the manufacturer's specification sheet for the pipette model and from your lab's written competency policy. | Pattern in the data | Most likely meaning | Documentation action | |--|--|--| | Mean on target, low scatter | Competent technique on a calibrated pipette | Record pass with numbers | | Mean on target, high scatter | Inconsistent technique, most often plunger speed or timing | Record fail or restricted pass, name the habit in feedback | | Mean off target, low scatter | Consistent personal bias, such as always under-aspirating at low volume, or a tip or pipette mismatch | Record the bias, check tip lot and pipette verification, retrain | | First reading of each series is an outlier | Skipped pre-rinse | Record the observation, coach pre-rinsing, repeat the series | | Values drift steadily across the series | Evaporation from the weighing vessel or warming of the tip | Note the elapsed time and vessel condition, repeat with a fresh vessel | | Good at 100 percent, poor at 10 percent | Small volume technique deficit, the most common trainee profile | Restrict authorization to higher volumes pending reassessment | The pattern in the last row deserves emphasis because it is the single most common result in real training sessions. Operators who are competent at 500 µL often fail at 50 µL with the same pipette, because every technique error is proportionally larger against a smaller target. Documentation that tests only the comfortable mid-range volume produces records that overstate competency. Always test the low end. ## Troubleshooting | Symptom | Likely cause | Fix | |--|--|--| | Trainee's scatter is high but the trainer's reference series was tight | Trainee technique, not the instrument | Focus retraining on plunger release speed and consistent timing | | Every reading in a series is low by a similar amount | Tip not sealed, wrong tip for the pipette, or volume dial not fully clicked into position | Check tip seating and dial detent, repeat the series | | Readings bounce between high and low at small volumes | Tip immersion too shallow or water surface disturbed by rapid pipetting | Slow the cycle, deepen immersion to 2 to 3 mm, use a wider vessel | | Mass readings decline across the series | Evaporation from the weighing vessel | Use a vessel with a small water pool at the bottom, work faster, keep the draft shield closed | | Balance reading will not stabilize | Static charge on plastic vessels or drafts | Use glass or metal vessels, close the draft shield, ground static if the lab has provisions | | Bubbles appear in the tip during aspiration | Aspiration too fast or tip inserted while liquid is foaming | Slow the plunger release, aspirate from below the foam layer, pre-rinse | | Gravimetric check impossible below about 10 µL because balance resolution is insufficient | Balance readability too coarse for the volume | Use a semi-micro or ultramicro balance, or switch to a photometric check per manufacturer documentation | | Trainee passes but routine work is still inconsistent | Training was done at only one volume or one pipette | Extend documentation to cover the volume range and pipette classes actually used | ## Variations **Multichannel pipettes.** Document each channel or, at minimum, a defined subset such as channels 1, 4, and 8 for an 8-channel pipette, because channel-to-channel variation is a real instrument property that trainee technique cannot average away. The technique checklist adds items such as vertical tip loading into the reagent reservoir and visual confirmation that all tips are seated. **Positive displacement pipettes.** These use a piston that contacts the liquid directly and are the correct choice for viscous, volatile, or dense solutions. The documentation looks the same, but the technique checklist changes, because positive displacement operation involves different plunger behavior and requires matching pistons and capillaries or tips as a set. Record the piston or capillary lot with the tip lot. **Serological pipettes and electronic pipettors.** For trainees who will use a pipet controller with serological pipettes, document volume setting accuracy on the device, whether used, and visual meniscus reading technique against the graduated marks. Electronic pipettors add mode selection (forward, reverse, repetitive dispensing) to the checklist, and the record should state which modes the trainee was assessed on. **Photometric and colorimetric checks.** When a balance of sufficient readability is unavailable, some labs verify delivery with a dye solution of known absorbance coefficient, measuring the diluted spot in a spectrophotometer or plate reader. This is a recognized alternative described in manufacturer technical documentation. Record the dye solution identity, dilution, wavelength, and the reference absorbance data, and note that the uncertainty is generally higher than a good gravimetric check at small volumes. **Group training sessions.** Multiple trainees can share one session and one instrument verification, but each trainee gets an individual gravimetric data series and an individual signed record. One shared form for a group is a documentation failure, because competency is an individual property. ## Records, Storage, and Stability of Documentation Training records have a life cycle, and the record itself should state that life cycle. Store completed, signed records in the lab's training binder or training management system, indexed by trainee name so all of a person's records sit together. Retain records for at least the duration of the person's affiliation with the lab, and longer if institutional or accreditation policy requires it. Many organizations keep training records for several years after separation, and the specific period is set by your institution rather than by a universal rule. Keep the records that the training record points to. The pipette calibration certificate or in-house verification record, the balance check weight log for the training date, and the tip lot documentation should all be retrievable from the numbers written on the training form. A training record that references a certificate that cannot be found is significantly weaker than one whose chain of documents is intact. Reassessment is part of stability. Record the reassessment due date on the form and enter it in whatever tracking system the lab uses for calibrations and training renewals, so the two review cycles are visible in one place. A record with no reassessment date documents a single event, not a maintained competency. ## Pipette Calibration Records Versus Training Records These two documents are often confused, and the confusion causes real gaps. A pipette calibration record describes the instrument. It contains the pipette identity, the test volumes, the as-found and as-left accuracy and precision measurements, the standard applied, the service provider or technician, and the next due date. It says nothing about any particular person. A pipetting training documentation record describes the person. It contains the trainee and trainer identities, the technique checklist, the trainee's own gravimetric data, and the competency decision. It says nothing about the instrument beyond a reference to its calibration status. A lab needs both, and each must cite the other. When a downstream experiment fails, the investigation asks two separate questions, was the pipette in calibration on that date, and was the operator competent on that date. Two separate, cross-referenced records answer them cleanly. A single conflated record answers neither. ## Common Mistakes and Limitations **Recording summaries without raw data.** A form that shows only "CV 0.8 percent, pass" cannot be reviewed for outliers, drift, or data transcription errors. Always record the ten individual readings. **Testing only the mid-range volume.** A trainee certified at 500 µL may be unreliable at 50 µL, and the record will not reveal it unless both volumes were tested. Test at 100 percent and 10 percent of nominal at minimum. **Skipping the balance check weight entry.** Without it, every mass reading in the record rests on an unverified assumption about the balance. The check weight entry takes one minute. **Documenting from memory hours later.** Individual readings, anomaly notes, and checklist scores degrade quickly after the session. Record in real time on the bench. **Using an overdue or damaged pipette for training.** The session must be repeated with a verified instrument, and the record must state which instrument was used. Trainees also absorb the wrong lesson about equipment discipline when labs train on out-of-tolerance tools. **Treating the checklist as optional.** Numbers tell you that something is wrong. The checklist tells you what to fix. A record without technique observations produces a failed trainee with no path to passing. **Letting the pass threshold float.** If the trainer applies an unstated mental standard, two trainees with identical data can receive different outcomes. Write the criteria, including the lab's trainee-specific tolerance, on the form before the session starts. **Confusing training with calibration.** As described above, they are different documents about different subjects, and using one where the other belongs leaves an audit-visible hole. **One honest limitation.** A training record proves competency at the tested volumes, with the tested pipette and tip lots, on the test date, with water as the test liquid. It does not certify performance with every reagent in the lab. Viscous, volatile, dense, or hazardous solutions each require technique adjustments, and the record should note which solution types the trainee was not yet assessed on. ## Frequently Asked Questions ### How long should pipetting training records be kept? Keep them for at least the duration of the person's affiliation with the lab, and longer if your institution's records policy requires it. Many organizations retain training records for several years after a person leaves, and the specific period is set by institutional or accreditation policy rather than a universal rule. ### What is the difference between pipette calibration and pipetting training documentation? Calibration records describe the instrument and its measured accuracy and precision. Training documentation describes the person, their technique assessment, their own gravimetric results, and the competency decision. A complete quality system keeps both and cross-references them. ### Which volumes should be tested during the training check? Test at 100 percent and 10 percent of the pipette's nominal maximum volume, with ten replicate deliveries at each. The 10 percent point is where trainee technique differences appear most clearly, so it should never be skipped. ### What coefficient of variation is acceptable for a new trainee? There is no universal number. Compare the trainee's results against the manufacturer's precision specification for that pipette model at the tested volumes and against your lab's written competency threshold, which is typically set slightly above the manufacturer's specification to allow for human variation. ### Can colored dye solutions be used instead of water for the training check? Yes, as an alternative when a balance of sufficient readability is not available, using a dye solution with a known absorbance coefficient measured on a spectrophotometer or plate reader. Gravimetric checking remains the preferred method for most volumes because its uncertainty is lower. ### Do multichannel pipettes need separate documentation? Yes, in the sense that the record must state which channels were tested, because channel-to-channel variation is an instrument property. Many labs test a defined subset of channels and document the subset explicitly. ### What events require a retraining entry rather than just a new calibration? A failed or marginal competency check, an extended absence from the bench, a move to a new pipette class such as multichannel or positive displacement, and assignment to a new assay type with different volume demands. Calibration of the pipette itself is a separate instrument event and does not replace a retraining record. ### What triggers an immediate pipette check outside the regular calibration schedule? Any drop onto the bench or floor, any immersion of the instrument body in liquid, visible damage, and any repair or seal replacement. When these events occur, run a gravimetric verification before returning the pipette to service and file the result in the instrument history.