Medical Laboratory Technology and Diagnostics

01Purpose and scope

• This manual supports the course Medical Laboratory Technology and Diagnostics. It describes how laboratory professionals carry out the work that clinicians depend on when they order tests, from receiving a specimen through to releasing a verified result. The focus is on routine clinical chemistry, hematology, microbiology, immunology, and molecular testing as they are commonly run in hospital and reference laboratories.
• The manual is a working reference, not a substitute for formal training, local standard operating procedures, or accreditation requirements. Practice varies with laboratory size, the test menu, and the regulatory setting. A small outpatient laboratory may send most complex assays to a reference laboratory, while a large academic center may develop and validate its own tests in house.
• Guidance on diagnosis, treatment, and the interpretation of an individual patient's results belongs to licensed clinicians. Laboratory staff provide analytical results and may raise concerns about a specimen or a value, but they do not make clinical decisions. This guidance does not replace qualified professional judgment, approved procedures, or required authorization. Where rules depend on jurisdiction, check the current requirements of the national or state authority and the accrediting body that applies to your laboratory. In the United States, that starts with the Clinical Laboratory Improvement Amendments rules administered by the Centers for Medicare and Medicaid Services.

02Core principles

• Every result should be traceable to a specimen, a verified patient identity, a validated method, and the people who performed and reviewed the work. If any link in that chain cannot be shown, the result is not reliable enough to release without investigation.
• Accuracy and timeliness both matter. A correct result that arrives after a treatment decision has already been made has limited value, while a fast result that is wrong can cause harm. Laboratories set turnaround time targets for each test priority, such as stat or routine, and track performance against them.
• Many laboratory errors arise before the sample reaches an analyzer. Collection technique, labeling, transport time, and storage temperature all shape the result, so attention to these steps is part of the analytical work rather than a separate task handled by someone else.
• Standardization reduces variation between shifts, staff members, and sites. A procedure written once and followed the same way each time makes results comparable over time and gives investigators a fixed reference when something goes wrong.
• Confidentiality governs every handoff. Specimen labels, worklists, and reports carry protected health information and must be handled under the privacy rules that apply where you work.

03Planning and preparation

• Begin by reviewing the test request. Confirm the patient name and a second identifier, date of birth, collection date and time, specimen type, and the ordering provider. Incomplete or conflicting requests should be held and clarified before testing starts, and every call to the ordering office should be documented with the name of the person contacted and the outcome.
• Method selection and verification come next. A commercially cleared or previously validated method still needs to be verified in your laboratory before patient results are reported. Verification typically confirms precision, accuracy against a comparison method or reference material, the reportable range, and whether the reference interval suits your patient population. The output is a verification file that a reviewer can read without asking the bench staff what they did.
• Staffing and competency need planning too. Assign only qualified staff to each method, and complete a documented competency assessment for each person before they run patient samples independently. Recheck competency on a schedule your procedure sets and after any major change in instrument, method, or personnel.
• Check supplies before each run. Confirm that reagents, calibrators, and controls are within expiration, that lot numbers are recorded, and that storage temperature logs are in range. Buying in large quantities can lower unit cost, but the trade-off is waste from expired stock and the risk of a lot change arriving mid-study.
• Identify stakeholders early. Clinicians and nursing units depend on turnaround time and critical value notification. The laboratory medical director or pathologist is responsible for test interpretation policy and sign-off on validations. Infection prevention, information technology staff who maintain the laboratory information system, the quality manager, and external inspectors all shape what the laboratory must document.

04Recommended workflow

1. 1
   : Receive and log the order in the laboratory information system. Compare the electronic order with the paper or electronic requisition and the specimen label. Reject or hold any specimen that fails the written acceptance criteria, such as a wrong tube type, insufficient volume, improper temperature, or missing identifiers, and record the reason and the notification made to the collecting unit.
2. 2
   : Accession the specimen. Assign a unique laboratory identifier, print or apply labels, and confirm that the identifiers on the tube, the label, and the electronic record match. Many laboratories check identifiers at more than one point, because a single check at the bench is easy to miss under workload pressure.
3. 3
   : Prepare the specimen according to the method's requirements. This may include centrifugation, aliquoting into secondary tubes, or dilution. Inspect the sample for hemolysis, lipemia, icterus, clots, and bubbles, and record any interference index or visual finding that could affect the result, since many analyzers flag these conditions but do not correct for them.
4. 4
   : Perform quality control before patient testing. Run control materials at the frequency and concentration levels defined in the procedure, and evaluate them against the acceptance rules in your SOP. Some laboratories use Westgard multirules and others use simpler limits, so the method of evaluation should be stated in the procedure rather than left to individual judgment. Do not release patient results when control performance is unacceptable.
5. 5
   : Analyze patient specimens. Follow the sequence on the worklist, observe run-specific instrument messages, and apply dilution or repeat procedures exactly as written. Record any instrument flag, error code, or deviation in the run log, including the operator and time.
6. 6
   : Review results before release. Compare each result with delta check limits, expected ranges, and critical value lists. Investigate outliers by checking the specimen for interference, reviewing the instrument trace, and comparing against the patient's previous results when available. Repeat testing when the procedure calls for it, and avoid repeating a sample simply to obtain a more convenient number.
7. 7
   : Verify and release. A qualified individual authorized by the laboratory reviews and releases the result, adds required comments such as specimen quality notes or method limitations, and communicates critical values to a licensed caregiver. Record the name of the recipient, the time of the call, and a read back confirmation according to your policy.
8. 8
   : Store specimens and records. Retain the specimen, the instrument data, and the QC records for the period set by your retention policy and applicable regulations. Dispose of biological waste through the approved stream, and archive electronic records so that an audit can reconstruct what happened for any reported result.

05Quality checks, risk controls and compliance

• Internal quality control detects analytical drift from day to day, while external proficiency testing compares your results with those of other laboratories using the same or different methods. Under the Clinical Laboratory Improvement Amendments in the United States, laboratories performing regulated tests must meet requirements for quality control, personnel, proficiency testing, and records, and the specific requirements depend on test complexity. Check the current text of the rule and the applicable state requirements, because states may add their own obligations.
• Accreditation programs add another layer. ISO 15189 describes quality management and technical requirements for medical laboratories, and accrediting bodies such as the College of American Pathologists publish checklists that inspectors use. Each program has its own scope and cycle, so confirm which one applies to your laboratory and keep a current copy of the checklist used at your last inspection.
• Risk control starts with identifying what could go wrong at each step. A simple failure mode review can list the step, the possible failure, its likely effect on a patient, and the control in place, such as a second identifier check or a limit on how long a specimen may wait before centrifugation. Prioritize controls for failures that could cause serious harm, even when they are uncommon.
• Biosafety is a separate and serious concern. Laboratory staff routinely handle blood and body fluids and sometimes cultures of infectious organisms. Follow the guidance in the Biosafety in Microbiological and Biomedical Laboratories publication, the occupational exposure rules administered by the Occupational Safety and Health Administration in the United States, and your institution's exposure control plan. Use biosafety cabinets for aerosol-generating work, handle sharps with engineering controls, and keep chemical safety data sheets available at the bench.
• Regulated and high-risk decisions require qualified sign-off. Critical result policies, test discontinuation, and changes to reference intervals should be approved by the laboratory director or other authorized person under your governing documents, not by a bench technologist acting alone.

06Collaboration and documentation

• Document control is the foundation of reliable practice. Each standard operating procedure should have an owner, a version number, an effective review date, and a record of who approved it. Old versions should be removed from the bench so that staff do not work from outdated instructions, and every change should be communicated and trained before it takes effect.
• Records must show what was done, by whom, and when. Use the laboratory information system audit trail for result changes, and require a reason for each corrected or amended report. Logs for temperature, QC, maintenance, and reagent preparation should be legible, complete, and reviewed on a schedule by someone other than the person who made the entries.
• Communication with clinicians works best when the laboratory states its expectations clearly. Publish specimen requirements, collection instructions, and expected turnaround times, and make the laboratory's phone number visible on requisitions. When a specimen is rejected, the message should say what is wrong and what the collecting unit can do to fix it.
• Shift handover is a common point of error. Use a written handover that lists instrument status, open repairs, pending repeats, unresolved QC issues, and any results on hold. Joint review of significant discrepancies between a laboratory result and the clinical picture is useful, provided the review stays focused on the analytical process and the documentation, not on blame.

07Measures and continuous improvement

• Choose a small set of indicators that reflect the work. Common examples include the percentage of results released within the target turnaround time, the specimen rejection rate by collecting unit, the QC failure rate by method, the proficiency testing score, the rate of amended or corrected reports, and the time from a critical result to notification. Set targets locally based on your test menu, your clinical partners, and your past performance, rather than adopting a number from another laboratory without understanding how it was measured.
• Review indicators on a regular schedule, and look at trends rather than single points. A rise in rejected specimens from one ward may point to a collection training gap, while repeated QC failures on one analyzer may point to a maintenance or reagent problem. Keep the denominator and the definition of each indicator written down so that the numbers can be compared over time.
• Improvement projects can follow a plan, do, study, act cycle. Choose one problem, make a small change, measure the effect for a defined period, and decide whether to keep, adjust, or abandon the change. Changes that reduce one delay can add pressure elsewhere, such as batching specimens to save analyzer time at the cost of longer turnaround for urgent samples, so review the whole workflow and not only the step under study.
• Measure the cost of improvement as well as the benefit. Automation can reduce hands-on time and error, but it requires service contracts, validation, staff training, and sometimes a rebuilt workflow. A realistic assessment includes these costs, and the decision belongs to the laboratory leadership with input from the medical director.

08Common mistakes and how to prevent them

• Mislabeling is among the most serious errors. Prevent it by labeling tubes at the bedside in the presence of the patient when practical, by using barcode scanning with a rule that unscanned specimens are not processed, and by checking identifiers at accession and again before release.
• Running patients on an analyzer with failed or unreviewed QC is another frequent problem. Build a hard stop into the system where possible, so that results cannot be released until QC is accepted, and make the rule visible on the bench.
• Transcription errors occur when results are copied by hand from an instrument printout or a screen. Where possible, use bidirectional interfaces so that values pass directly to the laboratory information system, and check manual entries against the source during review.
• Introducing a method without adequate verification is a common shortcut when a new analyzer arrives. Copying validation data from a manufacturer or another site does not replace local verification, because sample types, staff technique, and patient populations differ.
• Ignoring interference indices is a quiet risk. A hemolyzed sample may give a falsely high potassium result, and the analyzer may flag it without stopping the run. Train staff to read the flags, to comment on the report when a result may be affected, and to recollect when the procedure requires it.
• Releasing results before review is a tempting way to meet a turnaround target. Enforce the review step in the system, and track any results released without the required review as a nonconformance.
• Failing to document repeats and dilutions makes investigations almost impossible. Record every repeat, dilution, and reason for rerun in the run log so that an auditor or clinician can see the full history of a result.

09Practical checklist

• Confirm the test request has two patient identifiers, collection time, specimen type, and ordering provider before testing.
• Check the specimen against written acceptance criteria and document every rejection with the reason and the notification made.
• Verify that labels, tubes, and electronic records match at accession and again before release.
• Confirm that quality control is in range and acceptable before running patient samples, and record the evaluation method used.
• Review interference flags, delta checks, and critical value lists for every result before release.
• Document each repeat, dilution, and corrected report with the reason, the operator, and the time.
• Check reagent expiration, lot numbers, and storage temperature logs at the start of each shift.
• Confirm that the current version of each procedure is at the bench and that staff competency records are up to date.
• Review turnaround, rejection, QC failure, and amended report indicators on the scheduled review date and record actions taken.

★Learning sources

• Micro Degree: Medical Laboratory Technology and Diagnostics
• Micro Degree: Healthcare Administration Practice
• Micro Degree: Physiotherapy Assistant Operations
• Micro Degree: Cardiac Care Support