Medical Laboratory Scientist Certification – MLS (ASCP)

The medical laboratory scientist (MLS), sometimes referred to as a clinical laboratory scientist (CLS) or medical technologist (MT), performs a battery of highly specific analytical tests to assist doctors in reaching an accurate diagnosis regarding the patients who visit their office. And, due to the vital nature of this work, employment in this field is slated to rise significantly over the next decade; in fact, the Bureau of Labor Statistics (2016) predicts a 16 percent increase in jobs from 2014 to 2024, which equates to 52,100 new job openings. The BLS classifies this as “much faster” than average (7 percent) job growth. Individuals interested in pursuing a career in this field must meet certain requirements before being eligible to obtain certification through the American Society for Clinical Pathology (ASCP), the primary licensing body for the profession. While certification isn’t a requirement nationwide, a number of states do require licensure or certification to practice, including California, Florida, Georgia, Hawaii, Louisiana, Montana, Nevada, New York, North Dakota, Rhode Island, Tennessee, West Virginia, and the territory of Puerto Rico.

Preparation for becoming a medical laboratory scientist begins well before the individual sits for the exam through the ASCP; it can start as early as high school, where potential lab scientists will want to take as many lab-based science classes as possible to help prepare for the rigors of the MLS college curriculum and the difficulty of the certification exam. By starting the process as early as possible, an aspiring medical laboratory scientist can get a feel for lab work, and start building the necessary educational foundation to enter the profession and succeed in the role.

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Early Preparation in High School

To begin, as mentioned, an aspiring medical lab scientist should first take relevant courses during high school that will prepare him or her for later schooling and professional work. This may include courses in biology, chemistry, math, and other sciences. Furthermore, preparation should continue outside of the classroom as well; indeed, an aspiring medical laboratory scientist should consider searching for volunteer opportunities with local professionals to both achieve clinical volunteer experience, as well as to have a better idea of the scope and rigors of the job. Remaining diligent during this time will help the student become prepared for college or university, the certification exam, and life as a medical laboratory scientist.

Post-High School MLS(ASCP) Certification Preparation

Those working as medical laboratory scientists must first complete a four-year bachelor’s degree through an accredited college or university before they are eligible to sit for the certification exam through ASCP. Furthermore, ASCP provides that such students, during college or university, should take classes in mathematics, chemistry, and biology, which will help them prepare for the exam and the requirements of the career.

The most expeditious route to becoming MLS (ASCP)-certified is to ensure that one’s bachelor’s degree program is a National Accrediting Agency for Clinical Laboratory Sciences (NAACLS)-accredited medical laboratory science program because in that case completing the program in good standing is enough to qualify the student to sit for the MLS (ASCP) certification exam. Otherwise, the student must also fulfill additional requirements, including experience requirements that can add significantly to the timeline for becoming MLS (ASCP) certified.

That said, individuals do have the option of obtaining eligibility via a number of different routes. Specifically, for individuals who have not completed an NAACLS-accredited medical laboratory science program, these are the routes to certification:

  • Complete a bachelor’s degree from a regionally accredited four-year college or university with a sufficient course load in biology, chemistry and math; AND
  • Earn a medical laboratory technician MLT (ASCP) certification, and gain two (2) years of full-time acceptable clinical laboratory experience; OR
  • Gain five (5) years of full-time acceptable clinical laboratory experience; OR
  • For those who hold a valid but now-deprecated CLA(ASCP) certification, gain four (4) years of full-time acceptable clinical laboratory experience.

In some cases, a student may find that his or her eligibility overlaps among these categories; this is not a concern. As long as he or she can fit squarely within one of the sets of requirements, he or she is eligible to sit for the certification exam offered by ASCP in order to become a medical laboratory scientist. If, however, a student is missing one or more of the eligibility requirements in order to become certified, he or she should first achieve that before moving any further with ASCP.

MLS(ASCP) Certification Exam Preparation

Upon meeting all of the eligibility requirements to become certified as a medical laboratory scientist through ASCP, the individual should then decide on when he or she will sit for the certification exam. Before the aspiring medical lab scientist makes this decision, however, he or she should know what to expect on the day of the test. Going into the test unprepared may not yield positive results, and certainly could lead the individual to being required to take it again in the future.

Of course, there is no one specific method of study that will guarantee success on this exam. That said, there are certain ways to prepare, some of which are suggested by ASCP itself, which can help bolster an individual’s chances of succeeding on the exam.

Perhaps most importantly, the individual should read through the publications on the ASCP “suggested reading list” for aspiring medical laboratory scientists. An abridged list is included below:

  • Clinical Laboratory Science. Published by American Society for Clinical Laboratory Science. Washington, D.C.: ASCLS.
  • LabMedicine. Published by American Society for Clinical Pathology. Chicago: ASCP Press.
  • Medical Laboratory Observer. Published by NP Communications, Florida.
  • AACC Trainee Council
  • ASCP Online Practice Tests
  • CellAtlas – Blood Cell Morphology Guide
  • NACB Laboratory Medicine Practice Guidelines
  • AABB –
  • American Association for Clinical Chemistry (AACC) –
  • ASM Clinical Microbiology Portal –
  • Blood Bank Guy – Transfusion Medicine Education –
  • BloodLine Image Atlas (Hematology Images) –
  • Center for Disease Control and Prevention –
  • DPDx – CDC Parasitology Diagnostic Web Site –
  • Hematology Outlines –
    • Those interested in pursuing a certification as a medical laboratory scientist should understand that this is only a portion of a suggested reading guide prepared by ASCP. As such, anyone who wishes to work in this field should make a point to read as much relevant material as possible in order to ensure adequate preparation for the exam.

      Along with a suggested reading list, ASCP also provides an overview of the contents of the certification exam for students to use while preparing. While the overview of the contents does not list the exact questions that students will encounter, it does offer a comprehensive list of topics with which students should familiarize themselves before exam day, as well as the weight that each subject will have on the test. According to the ASCP website, the subjects that will be found on the certification examination, as well as their descriptions, are listed below:

      • Blood bank – Blood Group Systems, Antibody Screen & Identification, Crossmatch, DAT, Elution/Adsorption, Blood Donation, Transfusion Therapy, Transfusion Reactions, HDFN, Phenotyping/Genotyping, Antibody Titer, Pre-warm Technique.
      • Urinalysis and other bodily fluids – Physical, Chemical & Microscopic Urinalysis and Body Fluid Analysis (CSF, Amniotic, Synovial, Serous, Semen & Feces)
      • Chemistry – Carbohydrates, Acid Base, Electrolytes, Proteins & Other Nitrogen-Containing Compounds, Enzymes, Heme Derivatives, Lipids & Lipoproteins, Endocrinology, Tumor Markers, TDM, Toxicology.
      • Hematology – Erythrocytes & Leukocytes, Reticulocyte Count, ESR, Sickle Cell Test, Hemoglobin Electrophoresis, RBC Enzymes, RBC/WBC Morphology & Differentials, Platelets, Hemostasis
      • Immunology – Autoimmunity, Immune Responses, Physiology of the Immune System, Immunology of Viral & Microbial Infectious Diseases
      • Microbiology – General Microbiology, Aerobic Gram-positive Cocci, Gramnegative Bacilli, Gram-negative Cocci, Gram-positive Bacilli, Anaerobes, Fungus, Viruses, Mycobacteria, Parasites.
      • Laboratory operations – Quality Assessment/Troubleshooting, Safety, Management, Laboratory Mathematics, Instrumentation, Molecular Techniques, Education & Communication, Laboratory Information Systems

      Students with a strong grasp on the aforementioned subjects will likely have the best chances at succeeding on the MLS(ASCP) exam.

      Finally, in addition to the suggested reading list and the exam contents overview, ASCP also offers a number of online practice tests that are available for purchase. While the practice tests will likely not contain information identical to what will be found on a current exam, completing these sample tests can help an individual simulate test-date conditions.

State Licensure

As mentioned above, there are only a certain number of states that require individuals to be licensed or certified in order to practice as medical laboratory scientists. For more information about licensure in one of the aforementioned states, visit the ASCP’s website on state licensure.

In general, this is a thorough yet non-exhaustive list of the eligibility requirements for those interested in pursuing certification as a medical laboratory scientist through ASCP. Like any other career field, someone hoping to work in this profession should perform due diligence and learn as much as possible from all relevant agencies in order to have a strong grasp of what to expect throughout each step of the process.