KMLTTB common mistakes
KMLTTB · Understand the traps and how to avoid them.
When a scenario describes a result that is out of range or a QC failure, the candidate immediately chooses the corrective action (repeat the sample, recalibrate, report the result) instead of first choosing the step that establishes whether the result is valid, such as reviewing the control chart, checking Westgard rules, or verifying specimen integrity.
Candidates trained in bench workflow jump to troubleshooting because that is what they do in practice, and they read the question as 'what do you do next on the bench' rather than 'what does the quality system require first'. The exam sequences the steps of the testing process and rewards the earliest valid action.
What to do instead
Before answering any QC or out-of-range scenario, write the sequence on scratch paper: pre-analytical check, analytical verification (controls, calibration, rules), result validation, then action and documentation. Choose the option that matches the earliest unmet step in that sequence, not the most dramatic intervention.
The candidate answers ethics and professionalism items using personal moral opinion or general workplace courtesy, ignoring the specific instrument that governs the situation, such as the professional code of conduct, the laboratory's standard operating procedure, the regulatory requirement for confidentiality, or the obligation to report a colleague's error through the correct channel.
Ethics questions feel subjective, so candidates reason from intuition. The exam, however, tests whether the candidate knows the codified duty: patient confidentiality, competence limits, honest reporting, conflict-of-interest disclosure, and mandatory notification.
What to do instead
For every ethics item, identify the duty being tested and the document that creates it. Frame the answer as 'what does the code or regulation oblige me to do', prefer disclosure to the appropriate authority over informal handling, and prefer patient safety and accurate records over loyalty to a colleague.
The candidate confuses the roles of the regulator, the professional association, and the employing laboratory, for example assuming the association issues licences, that the employer can waive registration requirements, or that continuing professional development points are verified by the laboratory rather than the regulator.
In practice these bodies overlap in everyday conversation, and candidates hear 'the board', 'the society', and 'HR' used loosely. The exam tests precise institutional mandates, and the distractors are built from exactly these confusions.
What to do instead
Build a one-page comparison table with three columns (regulator, association, employer) and rows for registration and licensure, disciplinary authority, CPD requirements and audit, scope of practice, and employment conditions. Review it until each function is attached to the correct body.
On validation and verification items, the candidate treats the two terms as interchangeable and selects a verification activity (confirming a method meets the manufacturer's stated performance) when the scenario calls for validation (establishing performance for a new, modified, or in-house method), or omits the required performance characteristics such as precision, trueness, analytical range, and interference.
The words are used loosely in laboratories and both involve running samples. Candidates also memorise the concept without the checklist of parameters, so they cannot distinguish a complete protocol from a partial one.
What to do instead
Memorise the distinction as a sentence: verification confirms claimed performance, validation establishes it. Then memorise the parameter set (precision, trueness or bias, measuring interval, analytical sensitivity, interference, carryover, reference interval where relevant) and check each option against that list to see what is missing.
The candidate calculates a quality-control statistic or a diagnostic performance measure incorrectly because they apply the wrong formula, for example using the mean instead of the standard deviation as the divisor for a control range, or confusing sensitivity with predictive value when prevalence is given.
Under time pressure candidates rely on remembered shortcuts rather than deriving the quantity, and sensitivity and positive predictive value are easily swapped because both describe the probability of a positive result.
What to do instead
Practise with the 2x2 table every time: write true positives, false positives, false negatives, and false negatives into the cells before choosing a formula. For control statistics, write the formula, substitute numbers, and sanity-check that the control limit is wider than the standard deviation. Drill ten calculations per session until the derivation is automatic.
The candidate answers training and competence questions by describing attendance at a course or the accumulation of CPD points as sufficient evidence of competence, rather than describing documented assessment of knowledge and practical skill, with records retained and reassessment at defined intervals.
Candidates equate education with competence because courses are the visible activity. The exam distinguishes input (training events) from output (demonstrated and documented competence), and distractors describe plausible but insufficient activities.
What to do instead
For every competence item, ask whether the option includes observation or assessment of actual performance, a defined assessor, a record, and a review interval. Prefer options that combine direct observation with documented sign-off, and treat 'attended a workshop' alone as a distractor.
The candidate ignores the pre-analytical phase in scenario questions and focuses on instrument or reagent performance, missing that the described problem (haemolysis, wrong tube, delayed transport, mislabelled specimen, fasting status) is pre-analytical and requires specimen rejection or recollection rather than analytical troubleshooting.
Analytical work is the most technical and memorable part of training, so candidates overweight it. Pre-analytical errors are also described in narrative form, which makes them easy to skim past.
What to do instead
Read each scenario twice: first to list every fact about collection, transport, storage, and identification, second to consider the analytical data. If any pre-analytical fact is abnormal, test the rejection and recollection option first before considering instrument causes.
The candidate selects an answer that describes good practice but is not the required or documented action, for example choosing to 'inform the clinician verbally' when the scenario requires a documented critical result notification with read-back, time, and recipient recorded.
Verbally communicating a critical value is genuinely good practice, so the option feels correct. The exam tests the complete, auditable process, and partial actions are used as distractors.
What to do instead
When two options are both clinically sensible, choose the one that includes documentation, verification of receipt, and the correct channel. Treat any option lacking a record, a read-back, or a defined timeframe as incomplete unless the question explicitly asks for the immediate first action.
The candidate misreads negatively or absolutely worded stems, such as 'which is NOT required', 'except', or 'least appropriate', and selects the first true statement encountered instead of the exception.
Most items ask for the correct answer, so the reading habit is to confirm rather than negate. Under time pressure the negative word is missed entirely.
What to do instead
Circle or underline negation words as you read, and restate the stem in positive form before evaluating options ('which of these is not required' becomes 'three are required, one is not'). If you cannot find the exception, re-read the stem before re-reading the options.
The candidate runs out of time or answers unevenly because they spend excessive time on calculation-heavy or scenario-heavy items and leave professionalism or quality-management items unanswered, rather than allocating time by domain weight and flagging difficult items for review.
Calculations feel solvable with more time, so candidates over-invest in them, while shorter conceptual items are rushed. Without a timing plan, the final section is completed under pressure.
What to do instead
Before the exam, note the number of items and divide by the available time to get a per-item budget. In the first pass, answer every item you can within the budget, flag calculations, and return to them only after all items have an answer recorded. Practise full-length timed papers so the pacing is rehearsed.