DOH Histopathology Technologist oral exam prep

Knowledge: Fat does not freeze firmly at the temperatures that suit most tissues: lymph node cuts well at about minus 15 to minus 20 degrees C, but fatty tissue usually needs minus 25 degrees C or colder, so crumbling and smearing mean the block is too warm. I confirm two identifiers against the request before cutting, because a frozen section result changes the operation in real time. Unfixed tissue from a patient with past tuberculosis is a biosafety risk: cryostat cutting creates aerosols and fragments, and freezing does not kill mycobacteria. The pathologist may choose to trim the fat, cut only the node or use touch imprints. Frozen section has known false negatives, and permanent sections remain the final diagnosis.

Management: Immediately I would tell the pathologist about the tuberculosis history, so the choice between sections and imprints is theirs, and wear gloves, gown, eye protection and the respiratory protection policy requires. I would bring the block colder with the heat extractor or freezing spray, mount it on a pre-cooled chuck, and use a fresh blade with the anti-roll plate set correctly. I would cut sections of about 5 to 8 microns onto labelled slides, fix them at once and run a rapid H&E. After two failed attempts I would call the pathologist to the cryostat rather than keep theatre waiting. The residual tissue goes into formalin, labelled, for permanent sections. Afterwards I would decontaminate the cryostat as contaminated, following the manufacturer and policy, before any other specimen is cut.

Ethics and communication: If the container and form did not match, I would stop. The result goes to the surgeon only through the pathologist, never as my own impression. Any glove tear or exposure is reported to occupational health and through the incident system. The easily missed infection history is a learning point for theatre, raised without blame.

Reference: Bancroft's Theory and Practice of Histological Techniques (8th ed); WHO Laboratory Biosafety Manual, 4th edition (2020)

Knowledge: Ten percent neutral buffered formalin contains about 4 percent formaldehyde, which IARC classifies as a human carcinogen (Group 1) and which is also a sensitiser and an irritant to eyes, skin and airways. A large spill in a closed room can quickly exceed exposure limits; the US OSHA standard, for example, sets 0.75 ppm over 8 hours and 2 ppm over 15 minutes. The first harms are eye and airway irritation, and bronchospasm in sensitised people. Eye exposure needs at least 15 minutes of irrigation. The Safety Data Sheet and spill procedure define the protective equipment and neutralising absorbent. The specimens on the bench are irreplaceable.

Management: Immediately I would raise the alarm, clear people from the area and take my colleague to the eyewash, irrigating for at least 15 minutes, removing contaminated clothing and washing her forearm with water. I would arrange medical review for her and for anyone wheezing. If it takes only seconds and no further exposure, I would close the open containers so specimens stay labelled and fixed. A trained person in nitrile gloves, goggles, apron and the respiratory protection the SDS requires then contains the spill with neutralising absorbent from the edges inward. If the spill exceeds what we are trained or equipped for, I would evacuate and call the facility hazardous materials team. Waste goes into sealed, labelled containers for chemical disposal, never down the drain. The room reopens only after ventilation has cleared it, with air monitoring where available.

Ethics and communication: Colleagues' safety comes first, then the patients whose specimens are on the bench. I would report the spill and each exposure through the incident system and occupational health, without minimising it. If my colleague had not been trained in spill response, that is a system gap for the manager. I would tell the pathologist if any specimen was compromised.

Reference: OSHA Formaldehyde Standard, 29 CFR 1910.1048; IARC Monographs Volume 100F: Formaldehyde (2012); WHO Laboratory Biosafety Manual, 4th edition (2020)

Knowledge: Normal breast epithelium usually contains ER-positive cells, so absent staining there means the result cannot be read as negative, and a weak external control points to an analytical fault too. The ASCO/CAP ER and PgR guideline asks for fixation in 10 percent neutral buffered formalin for 6 to 72 hours, time to fixation as short as possible, and recording of ischaemia and fixation times; this core breaches both. Analytical causes include expired or wrongly diluted antibody, failed antigen retrieval, dispensing faults and dried sections. A false-negative ER denies endocrine therapy. The 2020 update reports 1 to 10 percent staining as ER low positive, which depends on reliable controls.

Management: Immediately I would hold the slide and tell the pathologist that both controls show an invalid run. I would check the run record: antibody lot and expiry, dilution, retrieval buffer and pH, instrument errors, and other ER slides on the same run. If the run failed, I would quarantine the suspect reagent and repeat on fresh sections with new controls, with instrument checks or vendor support. If normal ducts still do not stain, the pathologist may ask for testing on the excision specimen; that decision is theirs. I would make sure the ischaemia and fixation times reach the report. I would check whether results released from the same lot need review, and log the failure in quality records. I would not release a stain with failed controls to meet the meeting.

Ethics and communication: Honesty about a failed run matters more than turnaround. If earlier results were affected, the pathologist must know so clinicians can review treatment and disclose to patients in line with UAE law and facility policy. I would document each step and report the event through the quality system. I would never re-stain quietly and overwrite the record.

Reference: ASCO/CAP Guideline Update: Estrogen and Progesterone Receptor Testing in Breast Cancer (Allison et al, J Clin Oncol 2020); ASCO/CAP Guideline Update: HER2 Testing in Breast Cancer (Wolff et al, J Clin Oncol 2018); Dabbs, Diagnostic Immunohistochemistry: Theranostic and Genomic Applications

Knowledge: This looks like tissue transposed between two cases at grossing, a serious identification error that could give two patients the wrong diagnosis. Most such errors arise before analysis, at reception, grossing and cassette labelling, and having more than one case open at a station makes them likelier. These tissues look different, so this swap is easy to spot; swaps between similar tissues are more dangerous because they pass unnoticed. I would also consider a printing error or a container mix-up at reception. Processed tissue cannot be re-identified reliably by appearance, so DNA-based identity testing may be needed. Accreditation standards require two identifiers and an unbroken chain from container to slide.

Management: Immediately I would stop embedding both cassettes, keep them apart with their current labels, and not move tissue or change labels. I would inform the pathologist and the grossing colleague and, with them, check the remaining tissue in both containers, the gross descriptions, piece counts and any photographs. The pathologist decides which tissue belongs to whom, and corrections are made in the information system with an audit trail. If identity stays uncertain, the pathologist may arrange identity testing or discuss repeat biopsy, and the report states the problem. I would check the other cases grossed in that session. I would file an incident report the same day. The review should consider one case at a time on the bench, printed cassettes and a second identity check at embedding.

Ethics and communication: Both patients could be harmed, one by a missed cancer and one by a wrong skin diagnosis. Disclosure to patients is led by the pathologist and clinicians in line with UAE law and facility policy. My part is to report honestly, even when the colleague is a friend or senior. A no-blame approach keeps near misses being reported.

Reference: CAP Laboratory Accreditation Program, Anatomic Pathology Checklist; ISO 15189:2022 Medical laboratories: Requirements for quality and competence; WHO Laboratory Quality Management System Handbook (2011)

Knowledge: The cassettes are part way through dehydration. Tissue kept covered in alcohol is generally safe for some hours, whereas tissue that dries out, or sits too long in hot paraffin, becomes hard and brittle, and under-processed tissue is soft and crumbles at microtomy. A standard schedule runs formalin, graded alcohols, a clearing agent such as xylene and then paraffin, so I need the step where it stopped, whether tissue stayed covered and the state of the reagents. Restarting from the interrupted step with fresh reagents usually rescues the run. Small biopsies tolerate a shorter schedule; large or fatty blocks need full clearing and infiltration.

Management: Immediately I would inform the supervisor and the pathologist and would not drain or open the retort without a plan. I would read the log for the exact step, reagent levels and temperatures. If tissue stayed covered, I would restart from that step, or transfer cassettes to a second processor with fresh reagents, using a short programme for urgent biopsies and a full one for larger blocks. The pathologist tells clinicians about the delay. At embedding I would check each block; soft, poorly infiltrated tissue can be melted out, taken back through clearing agent and alcohol and re-infiltrated, as the pathologist directs. I would record each cassette's route. Afterwards I would arrange service of the processor and its power backup and an out-of-hours alarm alert. I would not cut obviously under-processed blocks to meet a deadline.

Ethics and communication: Patients with suspected cancer deserve an honest delay rather than a poor slide. I would report the failure through the incident and equipment fault systems, because power backup is a system issue. If any tissue is lost, the pathologist must know so the clinician can tell the patient and consider repeat biopsy.

Reference: Bancroft's Theory and Practice of Histological Techniques (8th ed); Carson and Cappellano, Histotechnology: A Self-Instructional Text

Knowledge: Patient health information is confidential, and in the UAE health data handling is governed by Federal Law No. 2 of 2019 on the use of information and communications technology in health fields, together with facility policy. My system access is for my work; opening a record without a work reason is a breach even if I share nothing, and audit trails record every access. Results should reach the patient from her clinician, who can explain them and plan treatment; a cancer diagnosis passed second-hand through relatives causes harm. Family involvement matters in GCC culture, but the patient decides who learns her information. Personal messaging apps are not approved channels for health data.

Management: I would not open the record, and I would reply kindly that I cannot access or share any patient's result. I would suggest the cousin call the clinic so the surgeon covering the service can see her. If the delay could harm the patient, I could tell my supervisor or the reporting pathologist that a signed-out result may have no clinician to act on it, without passing anything to the family. If my colleague pushes, I would repeat my position calmly and, if needed, inform my supervisor. I would not hint, send screenshots or answer yes or no. Had I already opened the record, I would report that access myself.

Ethics and communication: Confidentiality protects the patient's right to hear her diagnosis privately, with support. Kindness to a colleague does not override that duty, and a refusal can still be warm. If colleagues routinely shared results this way, I would raise it with the manager as a privacy and safety issue.

Reference: Federal Law No. 2 of 2019 on the use of information and communications technology in health fields (UAE); ISO 15189:2022 Medical laboratories: Requirements for quality and competence