What is a normal platelet-to-lymphocyte ratio?

In the Rotterdam Study of 8,711 adults aged 45 and over, the average was 120 and 95% had a PLR between 61 and 239. It is a little higher in women and rises with age. There is no agreed clinical cut-off.

How do you calculate PLR?

Divide the platelet count by the absolute lymphocyte count, both in ×10⁹/L (the same number as ×10³/µL). Platelets 210 and lymphocytes 2.0 give 105. Use the lymphocyte count, not the percentage.

Both are inflammation markers from the same blood count. NLR (neutrophils ÷ lymphocytes) is better studied and reacts faster to infection; PLR adds the platelets, which rise with longer-running inflammation. The SII combines all three.

Platelet-to-lymphocyte ratio (PLR) calculator

Short answer: PLR is platelets divided by the absolute lymphocyte count, both from a full blood count. In 8,711 healthy adults aged 45 and over it averaged 120, and 95% fell between 61 and 239. A higher PLR goes with inflammation; it is a research marker, not a diagnosis.

Free calculator

PLR calculator (platelet-to-lymphocyte ratio)

PLR = platelets ÷ lymphocytes (absolute counts)

Source: Fest J, Ruiter R, Ikram MA, Voortman T, van Eijck CHJ, Stricker BH. Reference values for white blood-cell-based inflammatory markers in the Rotterdam Study: a population-based prospective cohort study. Sci Rep 2018;8:10566.

Platelets

×10⁹/L

×10⁹/L is the same number as ×10³/µL or K/µL

Lymphocytes, absolute count

×10⁹/L

The count, not the %. Sometimes printed as ALC or LYM#

Your result

Enter the numbers from your lab report to see your result.

Worked out in your browser. Nothing you type is sent or saved.

A pointer, not a diagnosis. Talk to a doctor about your result, and sooner if you feel unwell.

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How to read the result

Below 61< 61Lower than in 95% of healthy adults in a large study. On its own it has no known meaning; look at your platelets and lymphocytes on the report.
61 to 23861 – 239In the range of 95% of healthy adults in a large population study.
239 or above≥ 239Higher than in 95% of healthy adults. It rises with infection, inflammation, surgery and some long-term illnesses; on its own it does not say which. If you feel unwell or it stays high, talk to a doctor.

Your lab’s range

PLR is not printed on lab reports and has no clinical cut-off for a healthy person. The bands are the 95% reference range of 8,711 adults aged 45 and over in the Rotterdam Study (average 120, range 61–239); it runs a little higher in women and with age. The markers it uses have lab ranges: platelets about 150–400 ×10⁹/L, lymphocytes about 1.0–4.0 ×10⁹/L.

How it is worked out

PLR = platelets ÷ lymphocytes (absolute counts)

Source

Fest J, Ruiter R, Ikram MA, Voortman T, van Eijck CHJ, Stricker BH. Reference values for white blood-cell-based inflammatory markers in the Rotterdam Study: a population-based prospective cohort study. Sci Rep 2018;8:10566.

The markers it uses

Platelet Count Lymphocytes Absolute Lymphocyte Count

Questions

What is a normal platelet-to-lymphocyte ratio?: In the Rotterdam Study of 8,711 adults aged 45 and over, the average was 120 and 95% had a PLR between 61 and 239. It is a little higher in women and rises with age. There is no agreed clinical cut-off.
How do you calculate PLR?: Divide the platelet count by the absolute lymphocyte count, both in ×10⁹/L (the same number as ×10³/µL). Platelets 210 and lymphocytes 2.0 give 105. Use the lymphocyte count, not the percentage.
PLR or NLR?: Both are inflammation markers from the same blood count. NLR (neutrophils ÷ lymphocytes) is better studied and reacts faster to infection; PLR adds the platelets, which rise with longer-running inflammation. The SII combines all three.

More calculators for the same system

NLR calculator ANC calculator Mentzer index calculator Sehgal index calculator SII calculator (systemic immune-inflammation index)

All blood test calculators

A pointer, not a diagnosis. Talk to a doctor about your result, and sooner if you feel unwell. Reference ranges are general-population guidance compiled from common clinical laboratories, not a diagnosis. Lab-to-lab ranges differ. Always read your results with your doctor.