ASCP MLS Reference Ranges: Important to Learn
The ASCP MLS reference ranges are a set of calculations or values that the lab scientist uses to interpret the patient test results.
The ASCP Board of Certification determines some reference ranges that are part of MLS ASCP exam content areas and are important to learn to pass the exam.
The ASCP BOC is very responsible for all its work, therefore, it offers all the necessary resources required for career development for its professionals.
From certification preparation to the recertification program, you will get all the resources and guidelines from the board.
For ASCP MLS exam preparation, the ASCP BOC presents ASCP MLS content guidelines, ASCP MLS reading lists, and ASCP MLS reference ranges.
Here, we will expose all the reference ranges that the board determines to learn before going for the final exam for ASCP medical laboratory scientists.
ASCP MLS Reference Ranges: Overview
The ASCP Board of Certification determines the following calculations and reference ranges:
ASCP MLS Calculation
- % Transferrin saturation/UIBC/TIBC
- Timed urine calculations
- Unconjugated/indirect bilirubin
- A/G ratio
- Creatinine clearance calculations
- Manual hemocytometer counts
- LDL/Friedewald equation/non-HDL
- Beer’s law
- Corrected WBC counts when > 10 nRBCs present
- Absolute cell counts given the relative values (e.g., WBCs, reticulocytes)
- Red blood cell indices (e.g., MCV, MCHC, and MCH)
ASCP MLS Reference Ranges: Valuable for Male and Female
Here, you will learn the ASCP MLS reference ranges for the following categories:
- Chemistry ASCP MLS Reference Ranges
- Hematology ASCP MLS Reference Ranges
- Body Fluids ASCP MLS Reference Ranges
Chemistry ASCP MLS Reference Ranges
| Conventional Unites | SI Unit | |
| Sodium | 136 – 145 mmol/L | 136 – 145 mmol/L |
| Potassium | 3.5 – 5.1 mmol/L | 3.5 – 5.1 mmol/L |
| Chloride | 98 – 107 mmol/L | 98 – 107 mmol/L |
| Total CO2 | 22 – 33 mmol/L | 22 – 33 mmol/L |
| Creatinine | 0.8 – 1.2 mg/dL | 71 – 106 µmol/L |
| Blood urea nitrogen (BUN) | 6 – 20 mg/dL | 2.1 – 7.1 mmol/L |
| Glucose (fasting) | 74 – 100 mg/dL | 4.1 – 5.6 mmol/L |
| Hemoglobin A1C | < 5.7% | < 39 mmol/mol |
| Haptoglobin | 30 – 200 mg/dL | 0.3 – 2.0 g/L |
| Arterial blood gases | ||
| pH | 7.35 – 7.45 | 7.35 – 7.45 |
| pCO2 | 35 – 44 mmHg | 4.7 – 5.9 kPa |
| pO2 | > 80 mmHg | > 10.6 kPa |
| O2 saturation | > 95% | > 95% |
| HCO3 – (bicarbonate) | 23 – 29 mmol/L | 23 – 29 mmol/L |
Hematology ASCP MLS Reference Ranges
| Conventional Units | SI Units | |
| RBC | 4.00 – 6.00 x 106 /μL | 4.00 – 6.00 x 1012/L |
| HGB | 12.0 – 18.0 g/dL | 120 – 180 g/L |
| HCT | 35% – 50% | 0.35 – 0.50 L/L |
| MCV | 76 – 100 fL | 76 – 100 fL |
| MCH | 26 – 34 pg | 26 – 34 pg |
| MCHC | 32 – 36 g/dL | 320 – 360 g/L |
| RDW | 11.5 – 14.5% | 0.115 – 0.145 |
| Reticulocytes (absolute) | 20 – 115 x 103 /μL | 20 – 115 x 109 /L |
| Reticulocytes (relative) | 0.5 – 2.5% | 0.5 – 2.5% |
| nRBCs | 0 nRBC/100 WBC | 0 nRBC/100 WBC |
| Platelets | 150 – 450 x 103 /μL | 150 – 450 x 109 /L |
| WBC (Total) | 3.6 – 10.6 x 103 /μL | 3.6 – 10.6 x 109 /L |
| Neutrophils (absolute) | 1.7 – 7.5 x 103 /μL | 1.7 – 7.5 x 103 /μL |
| Neutrophils (relative) | 50 – 70% | 0.50 – 0.70 |
| Lymphocytes (absolute) | 1.0 – 3.2 x 103 /μL | 1.0 – 3.2 x 109 /L |
| Lymphocytes (relative) | 18 – 42% | 0.18 – 0.42 |
| Monocytes (absolute) | 0.1 – 1.3 x 103 /μL | 0.1 – 1.3 x 109 /L |
| Monocytes (relative) | 2 – 11% | 0.02 – 0.11 |
| Eosinophils (absolute) | 0 – 0.3 x 103 /μL | 0 – 0.3 x 109 /L |
| Eosinophils (relative) | 1 – 3% | 0.01 – 0.03 |
| Basophils (absolute) | 0 – 0.2 x 103 /μL | 0 – 0.2 x 109 /L |
| Basophils (relative) | 0 – 2% | 0.00 – 0.02 |
Body Fluid ASCP MLS Reference Ranges
| Conventional Units | SI Units | |
| Cerebrospinal Fluid (CSF) | ||
| WBC and RBC | 0 – 5/μL | 0 – 5 x 106 /L |
| Glucose | 50 – 80 mg/dL | 2.8 – 4.4 mmol/L |
| Protein | 15 – 45 mg/dL | 150 – 450 mg/L |
| Seminal Fluid | ||
| Liquefaction | 30 – 60 minutes | 30 – 60 minutes |
| WBC | < 1 x 106 /mL | < 1 x 109 /L |
| Volume | 2 – 5 mL | 2 – 5 mL |
| pH | 7.2 – 8.0 | 7.2 – 8.0 |
| Motility | > 50% within 1 hour | > 50% within 1 hour |
| Sperm concentration | > 20 x 106 /mL | > 20 x 106 /mL |
| Morphology | > 30% normal forms | > 30% normal forms |
| Urine | ||
| Specific gravity | 1.003 – 1.035 | 1.003 – 1.035 |
| pH | 4.5 – 8.0 | 4.5 – 8.0 |
| Protein | < 10 mg/dL, trace, or negative | < 0.1 g/L, trace, or negative |
| Bilirubin | negative | negative |
| Blood | negative | negative |
| Glucose | ≤ 15 mg/dL or negative | ≤ 0.8 mmol/L or negative |
| Nitrite | negative | negative |
| Leukocyte esterase | negative | negative |
| Urobilinogen | < 1.0 EU | < 17.0 μmol/L |
| Ketones | < 5 mg/dL or negative | < 0.5 mmol/L or negative |
| Microscopic | ||
| RBC | 0 – 3/HPF | 0 – 3/HPF |
| WBC | 0 – 8/HPF | 0 – 8/HPF |
| Casts | 0 – 2 hyaline/LPF | 0 – 2 hyaline/LPF |
| Epithelial cells | 0 – 5/HPF | 0 – 5/HPF |
FAQs for ASCP MLS Reference Ranges
What is the meaning of ASCP MLS reference ranges?
The ASCP MLS reference ranges are the sets of values that you need to calculate the patient test results.
Why should I learn the ASCP MLS reference ranges?
You must learn these reference ranges because they are part of the ASCP MLS exam content area and valuable for your lab test result calculation.
Resources: ASCP BOC.
Abdelhalim Elshawadfy is an ASCP certified Medical Laboratory Scientist (MLS ASCP), Specialist in Microbiology (SM ASCP), and Molecular Biology Technologist (MB ASCP) with a distinguished career marked by expertise, continuous learning, and a commitment to elevating the standards of clinical laboratory science. As an ASCP Certification Expert and American Board Certification Expert, Abdelhalim Elshawadfy continues to make invaluable contributions to the field, leaving a lasting impact on the medical community.
