CCHT-A common mistakes
CCHT-A · Understand the traps and how to avoid them.
Computing urea reduction ratio with the wrong arithmetic - dividing by the post-BUN value, subtracting in the wrong order, or dropping the ×100 - and then choosing an answer that matches their miscalculation instead of the correct option.
Candidates memorize the shape of the formula under time pressure but not the meaning (percent of urea removed relative to the starting value), so they invert numerator and denominator or forget to convert the decimal to a percentage.
What to do instead
Write the formula from memory before starting calculation items: URR = (pre-BUN − post-BUN) ÷ pre-BUN × 100. Sanity-check every result: a clearance value below 0% or above 100% is impossible, and a typical adequate treatment lands near 65% or higher, so an answer of 12% or 180% signals an arithmetic error, not a knowledge gap.
Answering post-dialysis BUN sampling questions by describing a sample drawn immediately at the end of treatment at full pump speed, or drawn from the venous return line.
In real units the tech often just pulls a sample when treatment ends; the exam instead tests the standardized slow-flow/stop-pump collection method that prevents recirculation from falsely lowering the post-BUN and inflating the calculated clearance.
What to do instead
Study the post-BUN collection as a formal procedure: pump speed reduced to about 100 mL/min for roughly 15 seconds (or the stop-pump, wait-3-minutes method per protocol) before drawing from the arterial needle, with the exact stop time documented. Be able to explain why a fast or venous-line draw falsely improves the clearance number.
Treating infection control items as common sense and choosing the 'cleanest-sounding' option - for example skipping hand hygiene between patients when gloves were worn, or using alcohol alone on a catheter hub when the protocol requires a scrub with an antiseptic.
Glove use creates a false sense of protection, and candidates conflate 'sterile technique' with 'standard precautions' without linking a specific practice to a specific transmission route.
What to do instead
Build a one-page map: standard precautions apply to every patient (hand hygiene before and after every contact, gloves for anticipated blood exposure, never reuse or wash gloves); transmission-based precautions are added for diagnosed or suspected pathogens; vascular access care (catheter hub disinfection, fistula cannulation site prep) requires scrub time, not a quick wipe. Practice sorting scenarios into these three buckets until it is automatic.
When a conductivity alarm sounds, choosing the option that resets or overrides the alarm and continues treatment, or assuming the machine's displayed conductivity is sufficient proof that the dialysate is correct.
Alarms are frequent on the job and techs become desensitized to them; candidates transfer that 'silence and move on' habit into the exam instead of reasoning about patient risk from hypotonic or hypertonic dialysate.
What to do instead
Lock in the safe sequence and be able to state it in order: stop/isolate the patient from the dialysate circuit, verify the actual conductivity with an independent calibrated meter, check proportioning system and concentrate supply, and do not return the patient to treatment until the value is within the prescribed range. Remember that the internal monitor can drift - that is exactly why the independent meter exists.
Getting water treatment monitoring frequencies and limits wrong - for example saying chlorine/chloramine is tested weekly, or confusing a free chlorine reading with total chlorine when evaluating carbon tank performance.
These are numbers-and-schedule facts that feel interchangeable on a multiple-choice list, and candidates who have only watched the test being done (rather than performed and documented it) never anchored the frequency or the specific test name.
What to do instead
Memorize as paired facts: total chlorine (not free chlorine) is the test that detects chloramine breakthrough from carbon tanks; testing is performed at minimum before each patient shift and after carbon media is changed or tanks are rotated, with results documented and the carbon tanks monitored per the facility's water treatment protocol and AAMI/CMS expectations. Attach each fact to the consequence - chlorine breakthrough causes hemolysis - so the answer choice becomes obvious.
Calculating ultrafiltration rate from the fluid-removal goal alone, ignoring the saline used for priming, rinseback, and any intradialytic saline given, or dividing by minutes when the answer options are in mL/hour.
Candidates grab the most visible number (the target weight loss) and stop, treating the calculation as one step; unit conversion and hidden fluid volumes are the actual tested skill.
What to do instead
Use a fixed three-step template for every UF item: (1) total volume to remove = goal + prime/rinseback + saline infused − fluid taken in; (2) convert treatment time to hours; (3) divide volume by hours and label the unit. Write the unit next to your answer before looking at the options, and eliminate any option whose magnitude is off by a factor of 60.
Answering patient education items with a description of telling the patient the information once, thoroughly, at the start of treatment - and marking that as adequate teaching.
Lecture-style teaching is what many techs observe on the job, and the exam's 'best practice' option (assess, teach in small chunks, confirm with teach-back, document) looks slower and less complete than the candidate's own habit.
What to do instead
For every education scenario, apply the same checklist and pick the option that includes it: assess readiness, health literacy, and barriers first; teach one or two key points at a time; have the patient demonstrate or restate the information in their own words (teach-back); document what was taught and the patient's response, and plan reinforcement. Any option that only describes delivering information without confirmation is the distractor.
Selecting 'the patient did not understand the diet' as the explanation whenever a scenario describes missed treatments, large interdialytic weight gains, or high phosphorus - without first looking for practical and psychosocial barriers.
Nonadherence is easier to attribute to a knowledge deficit than to unpack transport problems, cost, depression, shift work, food insecurity, or an unrealistic fluid restriction, so candidates jump to re-education.
What to do instead
Treat every adherence scenario as an assessment question first. Before choosing any answer, ask whether the option gathers information (asks the patient what gets in the way, screens for depression, reviews transportation and finances, involves the dietitian or social worker) or jumps to a solution. Choose assessment and barrier-identification over repeat instruction, and reserve re-education for scenarios where the patient demonstrably lacks the knowledge.
Mixing up process measures and outcome measures in quality improvement items - for example calling the percentage of patients with a catheter a process measure, or labeling 'we audited cannulation technique' as an outcome.
Both types of measure are described in the same quality language on the unit's QAPI board, and candidates match on familiarity rather than on the structural definition of what is being counted.
What to do instead
Use a two-question test: does this measure count what we DID (process - hand hygiene audits, cannulation technique checks, chlorine testing compliance), or does it count what HAPPENED to the patient (outcome - infection rate, catheter use percentage, hospitalization, URR/Kt/V achievement)? Then be able to place it in the PDSA cycle: plan a change, do it small, study the data, act. Sort a list of ten measures into the two columns before exam day.
Answering scope-of-practice, regulatory, and 'who is responsible' items based on how their own unit happens to run, rather than on the CMS Conditions for Coverage and the technician's defined role under state and facility rules.
Local practice becomes the candidate's reference standard; when a unit has a strong nurse who informally delegates tasks, the candidate assumes the tech is accountable for them, and the exam's option reflecting the regulatory requirement looks wrong.
What to do instead
Anchor every professional-practice item in two facts: the technician performs care within a defined scope under the delegation and supervision of a licensed nurse, and the facility is accountable to the Conditions for Coverage for patient care, water and dialysate quality, reuse, and infection control regardless of local custom. When two options both sound reasonable, prefer the one that describes verification, documentation, and notification of the responsible licensed professional over the one that describes independently changing the plan of care.