by Lab managers read a medical laboratory scientist cover letter for certification, the bench areas you've worked, and the instruments you run. A generalist hospital lab wants rotation experience across sections; a reference lab hiring for blood bank or microbiology wants depth in that one area. Say which you're offering in the first paragraph.
BLS reports clinical laboratory technologists and technicians earned a median $62,930 in May 2025, with wide variation by role and setting (the lowest 10% earned under $38,910, the highest over $100,990), which reflects the gap between an entry-level MLT and a specialist MLS in blood bank or molecular testing. Hospitals employ the largest share of the occupation, though reference labs, physician offices, and public health labs also hire.
What to include
| Element | What it looks like for a medical laboratory scientist |
|---|---|
| Certification | MLS (ASCP) or equivalent (AMT, credential from your eligibility route) |
| State license | Required in some states (confirm current list); state license number if applicable |
| Bench areas | Chemistry, hematology, coagulation, microbiology, blood bank, urinalysis, molecular |
| Instruments | Sysmex, Beckman Coulter, Roche cobas, Vitek, Bio-Rad, by name |
| Complexity level | High-complexity testing under CLIA, waived/moderate testing if that's your setting |
| Volume | Specimens or tests processed per shift |
| QC/QA | Quality control runs, proficiency testing, corrective action documentation |
| LIS | Cerner, Epic Beaker, Sunquest, SoftLab |
| Specialist certs | SBB (blood banking), SM or SMB (microbiology), if held |
How to structure it
Four paragraphs on 1 page. Lab managers want to place you on a bench quickly, so lead with certification and specialty.
Opening: certification, bench focus, years, setting
State your certification, your primary bench area, and your setting. "MLS (ASCP) with 4 years in hospital core laboratory chemistry and hematology" tells the reader where you fit before anything else.
Proof: instruments, volume, and one catch
Name the instruments and LIS you use, then give a volume figure for a typical shift. Add one specific example: a critical value you called that changed a treatment plan, a specimen problem you traced to its source, or a QC failure you caught before results went out. Keep the example at the level of test type and process, not a specific patient.
Fit: their bench mix and their systems
Match your rotation or specialty experience to the posting's bench needs. If the lab runs an instrument or LIS you haven't used, name the closest one you know and how quickly you've picked up new platforms before.
Close: complexity level and availability
State your CLIA testing complexity experience if the posting specifies it, give your notice period, and thank the reader briefly.
Medical laboratory scientist cover letter example
Kevin is applying for a night-shift core lab position at a community hospital.
Dear Mr. Delacroix,
I'm applying for the Medical Laboratory Scientist II position on the night shift at St. Adeline Regional Medical Center. I'm certified as an MLS (ASCP) with 4 years of experience in a hospital core laboratory, covering chemistry, hematology, and coagulation.
I run a Roche cobas 8000 for chemistry and immunoassay, a Sysmex XN-1000 for hematology, and a Stago STA Compact for coagulation, and I process an average of 90 to 110 specimens a shift. Last winter I flagged a critical potassium result on a specimen that also showed hemolysis on visual inspection; instead of reporting it as-is, I requested a redraw, which came back normal and avoided an unnecessary cardiac workup. I document QC runs and corrective actions in Epic Beaker and have never had a proficiency testing failure go uncorrected.
Your posting lists microbiology cross-training as a plus. I rotated through micro for 6 months early in my career, reading plates and running a Vitek 2 for organism identification, and I'd welcome getting back into that rotation if the schedule allows.
I hold an active MLS license in Florida, since the state requires one for testing personnel, and I'm ready to provide documentation. I can start 3 weeks after an offer. Thank you for your consideration.
Sincerely,
Kevin Alvarado, MLS (ASCP)
(555) 927-4013 | kevin.alvarado@email.com
Why this example works
- Certification, bench focus, and setting are in sentence 1. A lab manager can place him mentally before reading further.
- Instrument names, by brand and model, tell the reader exactly what retraining he'd need, which matters more in a lab than a general skills list.
- The hemolyzed-specimen story shows judgment: he didn't just report a number, he questioned a preanalytical variable first. That's the habit lab directors screen for.
- He names his state's licensure requirement accurately instead of assuming it applies everywhere, which shows he understands his own state's rules rather than generalizing.
- The close is short and gives a clear start date.
Adjusting for your situation
New MLS graduate
Your clinical rotations are your experience. Name the program, the bench areas you rotated through, and any instrument you ran independently by the end.
I completed a NAACLS-accredited MLS program at the University of South Florida, including a 400-hour clinical rotation across chemistry, hematology, microbiology, and blood bank. By my final rotation I ran chemistry panels independently on a Roche cobas analyzer under supervision and completed daily QC without direction. I'm currently studying for the ASCP BOC certification exam and expect results within 6 weeks of applying.
Moving from a generalist bench to blood bank
Blood bank work carries higher stakes for identification errors, so name your experience with type and screen, crossmatch, and antibody workups directly.
For 3 years I've worked a rotating generalist bench, and for the last year I've spent 2 shifts a week in blood bank performing type and screens, crossmatches, and antibody identification panels on a Ortho Vision analyzer. I'm applying for a dedicated blood bank role because I want to build toward the ASCP Specialist in Blood Banking (SBB) certification, and I already follow our two-person identification verification process without exception.
Microbiology specialty
Microbiology postings want plate reading experience, organism identification methods, and susceptibility testing familiarity.
I've worked in hospital microbiology for 5 years, reading blood, urine, and wound cultures and performing organism identification and susceptibility testing on a Vitek 2 and BD Phoenix. I report critical organisms like MRSA and C. difficile directly to the ordering provider per our lab's protocol and track my turnaround time against our 24-hour target for routine cultures.
Lab professionals comparing coding and lab support roles can also see our medical coder cover letter for how a related health information role documents accuracy.
Mistakes to avoid
- Writing "medical technologist" or "MLS" with no certifying body named. Say MLS (ASCP) or the equivalent you hold.
- Assuming state licensure requirements apply everywhere. A small number of states license lab personnel; check your state's current rule before stating a license status.
- Listing bench areas with no instrument names. Labs standardize on specific platforms and want to know if you already run theirs.
- Giving a volume number with no time frame or bench area attached.
- Including a specimen story detailed enough to identify a patient.
- Applying to a specialty bench (blood bank, microbiology) with a generalist letter that doesn't mention that area at all.
Before you send it
- Certification named exactly, with the certifying body
- State license status confirmed for the hiring state, if that state requires one
- Bench areas and instrument names matched to the posting
- Specimen or test volume with a time frame
- 1 specific catch or QC example with no patient identifiers
- LIS named and matched to the posting
- CLIA testing complexity experience stated if relevant
- Start date and licensure or certification documentation readiness
More healthcare cover letters are collected in our cover letter examples. If your lab also staffs the draw station, our phlebotomist interview questions cover the specimen collection side of the same workflow.