Medical Laboratory Scientist Job Description Explained

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-27

Quick Answer

• Medical laboratory scientists perform diagnostic testing on patient samples and interpret results that guide clinical decisions, with duties varying by specialty area such as hematology, microbiology, chemistry, and immunology.
• The next practical step for prospective MLS candidates is to review the education and certification requirements for their state, since the U.S. Bureau of Labor Statistics reports that most clinical laboratory scientists hold a bachelor's degree and may need licensure depending on location.
• A key limitation is that MLS scope of practice, certification requirements, and job duties differ by employer and jurisdiction, so the information below provides general patterns instead of a universal job description.

Understanding the Medical Laboratory Scientist Role

The medical laboratory scientist, also called a clinical laboratory scientist or medical technologist, performs diagnostic testing on blood, body fluids, and other biological specimens. These professionals generate the laboratory data that physicians use to diagnose disease, monitor treatment, and manage patient care. The U.S. Bureau of Labor Statistics groups this occupation under clinical laboratory technologists and technicians, noting that these workers examine body fluids, tissues, and other specimens and that the results they produce help physicians detect and treat disease [<a href="#ref-1">1</a>].

The distinction between a medical laboratory scientist and a medical laboratory technician matters for career planning. The Bureau of Labor Statistics describes clinical laboratory technologists as typically needing a bachelor's degree, while clinical laboratory technicians usually complete an associate's degree or a certificate program [<a href="#ref-1">1</a>]. Technologists often perform more complex testing, interpret results, and take on supervisory responsibilities, while technicians focus on routine specimen processing and testing under supervision.

The work environment for medical laboratory scientists includes hospitals, diagnostic laboratories, physician offices, and outpatient care centers. The Bureau of Labor Statistics notes that clinical laboratory technologists and technicians work in these settings and that some may work evening, night, or weekend shifts because laboratories operate around the clock [<a href="#ref-1">1</a>]. This schedule reality matters for job seekers who need to plan for shift work and on-call responsibilities.

Core Responsibilities and Daily Workflow

The daily workflow of a medical laboratory scientist follows a predictable pattern that begins with specimen receipt and ends with verified results. The U.S. Department of Labor's O*NET OnLine database describes the tasks of clinical laboratory technologists, which include analyzing laboratory findings to check the accuracy of results and entering data into laboratory information systems [<a href="#ref-2">2</a>]. These tasks form the backbone of the profession.

Specimen Collection and Processing

Medical laboratory scientists often oversee specimen collection procedures, though phlebotomists may perform the actual blood draws in many facilities. The scientist must verify that the specimen matches the patient identifier, that the correct tube or container was used, and that the specimen was transported under appropriate conditions. O*NET OnLine lists tasks such as collecting and processing specimens for analysis and performing quality control procedures to ensure accurate test results [<a href="#ref-2">2</a>].

Processing steps vary by specimen type. Blood samples may need centrifugation to separate serum or plasma. Urine samples may need to be transferred to preservative tubes. Tissue samples require fixation and processing for histology. Each step has a written procedure, and the scientist must follow it exactly to avoid compromising the sample.

Test Performance and Method Validation

The scientist performs tests using automated analyzers, manual methods, or a combination of both. Automated chemistry and hematology analyzers process large volumes of samples, while manual methods are used for specialized tests such as blood smears, cultures, and certain immunoassays. O*NET OnLine describes the work of clinical laboratory technologists as including the operation of automated equipment and the performance of manual tests [<a href="#ref-2">2</a>].

Method validation is a critical responsibility that occurs when a new test or analyzer is introduced. The scientist must verify that the method produces accurate and precise results across the reportable range, that the calibration is stable, and that the reference intervals are appropriate for the patient population. This work requires an understanding of statistics and quality control principles.

Result Interpretation and Verification

The interpretation of results is where the medical laboratory scientist exercises independent judgment. The scientist must recognize patterns that indicate instrument malfunction, specimen problems, or true clinical abnormalities. O*NET OnLine lists the ability to analyze test results and to identify abnormal findings as part of the clinical laboratory technologist role [<a href="#ref-2">2</a>].

For example, a complete blood count that shows a low platelet count may be a true finding or may be caused by a clotted specimen. The scientist must examine the sample, review the instrument flags, and decide whether to repeat the test, examine a blood smear, or report the result with a comment. This judgment directly affects patient care.

Result Reporting and Communication

The scientist enters results into the laboratory information system, verifies that the results match the patient and the test order, and releases them for review by the ordering clinician. Critical values, which are results that indicate a life-threatening condition, must be called to the clinician immediately. The scientist must document the notification and the name of the person who received the call.

Communication also extends to troubleshooting with clinicians. When a test result does not match the clinical picture, the scientist may need to discuss the result with the ordering physician, explain the limitations of the test, or recommend a different test. O*NET OnLine describes the work context of clinical laboratory technologists as including the need to communicate with others and to coordinate work with other laboratory staff [<a href="#ref-2">2</a>].

At a Glance

Specialty Areas and Their Distinct Duties

Medical laboratory scientists work across several specialty areas, each with its own procedures, instruments, and clinical questions. The Bureau of Labor Statistics describes clinical laboratory technologists as performing complex tests that may include analyzing blood, body fluids, and tissue samples [<a href="#ref-1">1</a>]. The specialty areas below reflect the common divisions in hospital and reference laboratories.

Hematology

Hematology scientists examine blood cells and blood-forming tissues. They perform complete blood counts, white blood cell differentials, and tests of coagulation. The scientist must recognize abnormal cell morphology on a blood smear, which requires visual skill and pattern recognition. The results help diagnose anemia, infection, leukemia, and bleeding disorders.

The hematology scientist also performs quality control on the analyzer, reviews the scatterplots and histograms generated by the instrument, and decides when to review a smear manually. A flag from the analyzer, such as a suspected blast or an abnormal platelet count, triggers a manual review. The scientist must determine whether the flag represents a true abnormality or an artifact.

Clinical Chemistry

Clinical chemistry scientists measure the concentration of chemicals, enzymes, and hormones in blood, urine, and other fluids. They operate automated analyzers that measure glucose, electrolytes, kidney function, liver enzymes, and cardiac markers. The scientist must understand the chemistry of each method, the interferences that can affect the result, and the clinical significance of the values.

The chemistry scientist performs calibration, runs quality control, and troubleshoots when results are out of range. A high potassium result may be a true finding or may be caused by hemolysis of the red blood cells during collection. The scientist must recognize the pattern and decide whether to repeat the test or report the result with a caution.

Hematology and Coagulation

The hematology and coagulation specialty overlaps with hematology but focuses on the clotting system. The scientist performs prothrombin time, partial thromboplastin time, and other coagulation tests. These results guide the dosing of anticoagulant medications such as warfarin. The scientist must recognize the effects of the medication and the limitations of the test.

Microbiology

Microbiology scientists identify the bacteria, viruses, fungi, and parasites that cause infection. They perform cultures, gram stains, and biochemical tests to identify the organism and determine its susceptibility to antibiotics. The scientist must interpret the growth patterns, the appearance of the colonies, and the results of the biochemical tests.

The microbiology scientist also performs molecular tests, such as polymerase chain reaction, to detect the genetic material of the organism. These tests are faster and more sensitive than culture but require careful technique to avoid contamination. The scientist must interpret the results in the context of the patient's clinical picture.

Immunology and Serology

Immunology scientists detect antibodies and antigens in the blood. They perform tests for autoimmune diseases, allergies, and infectious diseases. The scientist must understand the principles of the immunoassay, the potential for interference, and the clinical significance of the results.

Molecular Diagnostics

Molecular diagnostics scientists perform tests that detect the genetic material of the organism or the patient. They use techniques such as polymerase chain reaction, sequencing, and hybridization. The scientist must understand the principles of the molecular method, the controls, and the interpretation of the results. This is a rapidly growing area of the laboratory.

Blood Banking and Transfusion Medicine

Blood bank scientists determine the blood type of the patient and the donor, and they perform compatibility testing to ensure that the patient can safely receive a transfusion. They must understand the blood group systems, the antibodies, and the reactions that can occur. The scientist must interpret the results of the agglutination tests and decide whether the blood is compatible.

The blood bank scientist also manages the inventory of blood products and ensures that the products are stored and issued correctly. A patient with a rare antibody may require a special unit of blood, and the scientist must find a compatible unit.

Education and Certification Pathways

The education pathway for a medical laboratory scientist typically begins with a bachelor's degree. The Bureau of Labor Statistics reports that clinical laboratory technologists typically need a bachelor's degree, while technicians typically need an associate degree or a certificate [<a href="#ref-1">1</a>]. The degree program includes coursework in chemistry, biology, and laboratory science, and it includes clinical rotations in a hospital laboratory.

Accredited Programs

The degree program should be accredited by a recognized agency. The National Accrediting Agency for Clinical Laboratory Sciences (NAACLS) accredits programs in medical laboratory science. Graduates of an accredited program are eligible to sit for the certification examination offered by the American Society for Clinical Pathology (ASCP) or another certifying body.

Certification and Licensure

Certification is a voluntary credential that demonstrates competence, but many employers require it. The Bureau of Labor Statistics notes that some states require clinical laboratory personnel to be licensed, and that certification is often required for employment [<a href="#ref-1">1</a>]. The certification examination covers the knowledge and skills of the profession.

The specific certification and licensure requirements vary by state. A job seeker should check the requirements of the state where they plan to work. The Bureau of Labor Statistics provides a general description of the occupation, but it does not provide a list of state requirements [<a href="#ref-1">1</a>].

Continuing Education

The medical laboratory scientist must maintain the certification through continuing education. The certifying body requires a certain number of continuing education credits over a period of time. The scientist must document the credits and submit them for renewal.

Work Settings and Employment Sectors

Medical laboratory scientists work in a variety of settings, each with its own workflow and expectations. The Bureau of Labor Statistics describes the work settings for clinical laboratory technologists and technicians as including hospitals, diagnostic laboratories, and physician offices [<a href="#ref-1">1</a>].

Hospital Laboratories

Hospital laboratories are the largest employer of medical laboratory scientists. The laboratory operates 24 hours a day, 7 days a week, and the scientist works in shifts. The hospital laboratory offers a wide range of testing, and the scientist may rotate through the specialty areas.

Reference Laboratories

Reference laboratories are large, centralized laboratories that process samples from many hospitals and clinics. The scientist may work in a single specialty area, such as chemistry or microbiology, and may use highly automated equipment. The workflow is high-volume and the scientist must be efficient.

Physician Office Laboratories

Physician office laboratories are small laboratories that perform a limited number of tests. The scientist may be the only laboratory professional in the office and must perform all the duties, from collection to reporting. The scientist must be able to work independently and to troubleshoot problems.

Research and Federal Laboratories

The National Institutes of Health (NIH) offers training and career development for scientists, including those in the laboratory. The NIH Office of Intramural Training and Education describes the training and mentoring opportunities for scientists at various stages of their careers [<a href="#ref-3">3</a>]. The National Science Foundation (NSF) also employs scientists and technical staff in a federal research organization [<a href="#ref-4">4</a>]. These settings may require a different set of skills, such as research design and data analysis.

Practical Steps for Entering the Profession

The path to a medical laboratory scientist career involves several steps, from education to certification to employment. The following steps provide a practical framework for a job seeker.

Step 1: Complete the Required Education

The first step is to complete a bachelor's degree in medical laboratory science or a related field. The degree program should include coursework in chemistry, biology, and laboratory science, and it should include clinical rotations. The Bureau of Labor Statistics reports that clinical laboratory technologists typically need a bachelor's degree [<a href="#ref-1">1</a>].

Step 2: Gain Clinical Experience

The clinical rotations in the degree program provide the hands-on experience that is required for certification. The student performs the tests under the supervision of a clinical instructor and learns the workflow of the laboratory.

Step 3: Obtain Certification

After graduation, the graduate should sit for the certification examination. The certification demonstrates the knowledge and skills required for the profession. The certification is often required by the employer and by the state.

Step 4: Apply for State Licensure

If the state requires licensure, the scientist must apply for the license. The requirements vary by state, and the scientist should check the requirements of the state where they plan to work.

Step 5: Find a Position

The scientist can find a position in a hospital, reference laboratory, or clinic. The job search should include a review of the job description and the requirements of the employer.

Records and Measurements in the Laboratory

The medical laboratory scientist is responsible for the accuracy and the integrity of the laboratory records. The records include the test results, the quality control data, the maintenance logs, and the patient identifiers. The scientist must document the work in a clear and accurate manner.

Quality Control Records

The quality control records document the performance of the quality control materials. The scientist must run the quality control at the frequency specified by the laboratory, and the results must be within the acceptable range. The scientist must document the results and the action taken when the control is out of range.

Maintenance and Calibration Records

The maintenance and calibration records document the performance of the analyzers. The scientist must perform the maintenance and the calibration at the frequency specified by the manufacturer, and the records must be documented. The scientist must document the results and the action taken.

The Laboratory Information System

The laboratory information system (LIS) is the computer system that manages the laboratory data. The scientist enters the test results into the LIS, verifies the results, and reports the results to the clinician. The LIS also tracks the specimen, the test, and the result.

Common Failure Patterns and How to Avoid Them

The medical laboratory scientist must be aware of the common failure patterns in the laboratory and how to avoid them. The failure patterns include pre-analytical errors, analytical errors, and post-analytical errors.

Pre-Analytical Errors

Pre-analytical errors occur before the test is performed. The errors include the wrong specimen, the wrong collection, the wrong transport, and the wrong storage. The scientist must verify the specimen, the collection, and the transport to avoid the errors.

Analytical Errors

Analytical errors occur during the test. The errors include the instrument malfunction, the reagent, the calibration, and the quality control. The scientist must monitor the instrument, the reagent, and the quality control to avoid the error.

Post-Analytical Errors

Post-analytical errors occur after the test. The errors include the wrong result, the wrong entry, and the wrong report. The scientist must verify the result, the entry, and the report to avoid the error.

Quality and Safety Controls

The medical laboratory scientist must follow the quality and safety controls that are required by the laboratory and by the regulations. The controls include the quality control, the proficiency testing, and the safety.

Quality Control

The quality control is the process of ensuring that the test results are accurate and reliable. The scientist must run the quality control at the frequency specified by the laboratory, and the results must be within the acceptable range. The scientist must document the results and the action taken.

Proficiency Testing

The proficiency testing is the process of testing the unknown samples that are provided by an external agency. The scientist must test the samples and report the results to the agency. The agency evaluates the results and provides a score. The laboratory must pass the proficiency testing to maintain the accreditation.

Safety

The laboratory is a hazardous environment. The scientist must follow the safety procedures to avoid the exposure to the bloodborne pathogens, the chemicals, and the radiation. The scientist must wear the personal protective equipment, and the equipment must be used correctly.

Professional Development and Career Advancement

The medical laboratory scientist can advance the career through the education, the certification, and the experience. The career path includes the specialist, the supervisor, the manager, and the director.

Specialist Certification

The scientist can obtain the specialist certification in a specialty area, such as the hematology, the chemistry, or the microbiology. The specialist certification demonstrates the advanced knowledge and the skill in the specialty.

Supervisory and Management Roles

The scientist can advance to the supervisory and the management roles. The supervisor manages the staff and the workflow of the laboratory. The manager manages the budget, the personnel, and the quality of the laboratory.

Research and Education Roles

The scientist can also pursue the research and the education roles. The NIH provides the training and the career development for the scientists [<a href="#ref-3">3</a>]. The scientist can teach in the academic program, or can conduct the research in the laboratory.

Professional Development and Networking

The medical laboratory scientist should engage in the professional development and the networking. The American Society for Microbiology (ASM) provides the career services and the networking opportunities for the microbiologists [<a href="#ref-5">5</a>]. The Association of American Veterinary Medical Colleges (AAVMC) provides the career resources for the veterinary professionals [<a href="#ref-6">6</a>].

Continuing Education

The scientist must maintain the continuing education to maintain the certification. The education includes the courses, the workshops, and the conferences. The scientist must document the education and the submit the records.

Professional Organizations

The professional organizations provide the networking, the education, and the advocacy for the profession. The scientist should join the organization and the participate in the activities.

Limitations and Professional Escalation Criteria

The medical laboratory scientist must recognize the limitations of the role and the when to escalate the issue to the supervisor or the clinician.

Limitations of the Role

The scientist does not diagnose the disease or the prescribe the treatment. The scientist provides the data that the clinician uses to make the decision. The scientist must not interpret the results for the patient.

Escalation Criteria

The scientist must escalate the issue to the supervisor when the quality control is out of range, when the instrument is malfunctioning, or when the result is the critical value. The scientist must escalate the issue to the clinician when the result is the critical value or when the result does not match the clinical picture.

Frequently Asked Questions

What is the difference between a medical laboratory scientist and a medical laboratory technician?

A medical laboratory scientist typically holds a bachelor's degree and performs complex testing, result interpretation, and quality control. A medical laboratory technician typically holds an associate degree or certificate and performs routine testing under supervision. The Bureau of Labor Statistics describes the education difference between the two roles [<a href="#ref-1">1</a>].

What education is required to become a medical laboratory scientist?

A bachelor's degree in medical laboratory science or a related field is the typical requirement. The Bureau of Labor Statistics reports that clinical laboratory technologists typically need a bachelor's degree [<a href="#ref-1">1</a>]. The degree program includes laboratory coursework and clinical rotations.

Is certification required to work as a medical laboratory scientist?

Certification is often required by employers and by some states. The Bureau of Labor Statistics notes that some states require clinical laboratory technologists to be licensed and that certification is often required [<a href="#ref-1">1</a>]. The certification is obtained by passing an examination from a certifying body.

What are the main specialty areas in medical laboratory science?

The main specialty areas are hematology, clinical chemistry, microbiology, immunology, molecular diagnostics, and blood bank. Each specialty has its own testing, instruments, and quality controls. The scientist may rotate through the specialties or specialize in one area.

What is the work schedule for a medical laboratory scientist?

The work schedule depends on the setting. Hospital laboratories operate 24 hours a day, and the scientist may work shifts, including nights and weekends. Reference laboratories may have more regular hours. The Bureau of Labor Statistics describes the work settings for the occupation [<a href="#ref-1">1</a>].

What is the difference between a medical laboratory scientist and a research scientist?

A medical laboratory scientist performs clinical testing on patient samples to produce results for patient care. A research scientist conducts experiments to answer scientific questions. The NIH provides training and career pathways for research scientists [<a href="#ref-3">3</a>], while the clinical laboratory scientist works in a diagnostic setting.

What are the most important skills for a medical laboratory scientist?

The most important skills are attention to detail, the ability to follow procedures, the ability to interpret results, and the ability to communicate with clinicians. O*NET OnLine describes the skills and the work context for the occupation [<a href="#ref-2">2</a>].

How does a medical laboratory scientist advance in the career?

The scientist can advance through specialist certification, supervisory roles, and management roles. The scientist can also pursue research and education roles. The NIH provides the training and career development for the research [<a href="#ref-3">3</a>].

Using the Evidence

Related Articles

• What Does an Environmental Scientist Do? Roles and Responsibilities
• Bioinformatics Job Description: Roles, Responsibilities, and Skills
• Medical Laboratory Career Paths: From Technician to Director
• Laboratory Manager Career Path: Skills, Responsibilities, and Progression
• Bioinformatics Analyst: Job Description, Skills, and Career Path

References and Further Reading

This article is educational and does not replace institutional policy, professional advice, or applicable safety and regulatory requirements.