Platelet count
The platelet count is the number of platelets in blood. Many laboratories use 150 to 400 thousand/µL for everyone, while survey and cohort ranges differ by sex and age and run lower in older men. Low counts and high-normal counts were linked to more deaths in cohorts. Clumping in the collection tube can give a falsely low count.
- Status
- Part of the complete blood count, ordered by a clinician and also sold direct to consumers by some US laboratories. FDA classifies automated cell counters, which count red cells, white cells and platelets, as class II devices [1].
- Measures
- The number of platelets in a given volume of whole blood, counted by an automated cell counter.
- Also called
- PLT, Plt, platelets, platelet count, thrombocyte count, thrombocytes, CBC platelets
- Tested for
- bruising, bleeding, clotting, general checkup, pregnancy check, monitoring during medication, liver disease, low platelets, high platelets
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Linked in research4
- ModerateLinked to more deaths at low counts in two European cohorts, and at counts above 300 thousand/µL in one of them.
- ModerateLinked to bleeding in people with immune thrombocytopenia, with bleeding inside the skull in 1.4% of adults and 0.4% of children across pooled studies.
- LimitedLimited evidence: one English cohort found cancer within a year in 11.6% of men and 6.2% of women aged 40 and older with a count above 400.
- LimitedLimited evidence: one Danish cohort linked a count of 301 to 450 thousand/µL to 32% more cardiovascular disease than a count of 201 to 250.
Reported risks0
No risks sourced yet.
Reference ranges
Each range is the one its source published, in thousand/µL. Also reported in ×10⁹/L. Where sources differ, each is shown.
US national survey laboratory procedure manual, 2017 to 2018, men aged 19 to 65
Men aged 19 to 65, as the reference range used by the survey laboratory · [2]
| Range | What the source calls it |
|---|---|
| below 152 thousand/µL | No name given |
| 152 to 386 thousand/µL | "reference range" |
| above 386 thousand/µL | No name given |
The 2.5th to 97.5th percentiles of everyone measured in the US national survey from 1999 to 2004, calculated by ranking, without screening out people with illness. The survey reports the count in thousands of cells per µL, which is the same number as ×10⁹ per liter [2].
US national survey laboratory procedure manual, 2017 to 2018, men aged 66 and older
Men aged 66 and older, as the reference range used by the survey laboratory · [2]
| Range | What the source calls it |
|---|---|
| below 124 thousand/µL | No name given |
| 124 to 384 thousand/µL | "reference range" |
| above 384 thousand/µL | No name given |
Derived the same way from the 1999 to 2004 survey sample [2].
US national survey laboratory procedure manual, 2017 to 2018, women aged 19 to 65
Women aged 19 to 65, as the reference range used by the survey laboratory · [2]
| Range | What the source calls it |
|---|---|
| below 168 thousand/µL | No name given |
| 168 to 441 thousand/µL | "reference range" |
| above 441 thousand/µL | No name given |
Derived the same way from the 1999 to 2004 survey sample [2].
US national survey laboratory procedure manual, 2017 to 2018, women aged 66 and older
Women aged 66 and older, as the reference range used by the survey laboratory · [2]
| Range | What the source calls it |
|---|---|
| below 155 thousand/µL | No name given |
| 155 to 428 thousand/µL | "reference range" |
| above 428 thousand/µL | No name given |
Derived the same way from the 1999 to 2004 survey sample [2].
US national survey laboratory procedure manual, 2017 to 2018, boys aged 1 to 5
Boys aged 1 to 5, as the reference range used by the survey laboratory · [2]
| Range | What the source calls it |
|---|---|
| below 212 thousand/µL | No name given |
| 212 to 546 thousand/µL | "reference range" |
| above 546 thousand/µL | No name given |
Derived the same way from the 1999 to 2004 survey sample [2].
US national survey laboratory procedure manual, 2017 to 2018, boys aged 6 to 18
Boys aged 6 to 18, as the reference range used by the survey laboratory · [2]
| Range | What the source calls it |
|---|---|
| below 179 thousand/µL | No name given |
| 179 to 439 thousand/µL | "reference range" |
| above 439 thousand/µL | No name given |
Derived the same way from the 1999 to 2004 survey sample [2].
US national survey laboratory procedure manual, 2017 to 2018, girls aged 1 to 5
Girls aged 1 to 5, as the reference range used by the survey laboratory · [2]
| Range | What the source calls it |
|---|---|
| below 215 thousand/µL | No name given |
| 215 to 547 thousand/µL | "reference range" |
| above 547 thousand/µL | No name given |
Derived the same way from the 1999 to 2004 survey sample [2].
US national survey laboratory procedure manual, 2017 to 2018, girls aged 6 to 18
Girls aged 6 to 18, as the reference range used by the survey laboratory · [2]
| Range | What the source calls it |
|---|---|
| below 190 thousand/µL | No name given |
| 190 to 446 thousand/µL | "reference range" |
| above 446 thousand/µL | No name given |
Derived the same way from the 1999 to 2004 survey sample [2].
Nordic Reference Interval Project, 2004, women
Women aged 18 to 90 in Denmark, Finland, Iceland, Norway and Sweden · [3]
| Range | What the source calls it |
|---|---|
| below 165 thousand/µL | No name given |
| 165 to 387 thousand/µL | "reference interval" |
| above 387 thousand/µL | No name given |
The 2.5th to 97.5th percentiles in 1,826 healthy men and women, measured on 12 types of analyzer in 60 laboratories [3].
Nordic Reference Interval Project, 2004, men
Men aged 18 to 90 in Denmark, Finland, Iceland, Norway and Sweden · [3]
| Range | What the source calls it |
|---|---|
| below 145 thousand/µL | No name given |
| 145 to 348 thousand/µL | "reference interval" |
| above 348 thousand/µL | No name given |
From the same healthy sample [3].
Reference interval used by most clinical laboratories, as reported by Biino and colleagues, 2013
People of any age and either sex, as the single interval the authors report most clinical laboratories use · [4]
| Range | What the source calls it |
|---|---|
| below 150 thousand/µL | No name given |
| 150 to 400 thousand/µL | "reference interval" |
| above 400 thousand/µL | No name given |
The authors cite this interval as the one still in general use and argue against applying it to everyone, because the count is higher in women, falls with age and differs by genetic background [4]. A laboratory's own printed interval may differ.
Italian population studies, proposed reference intervals, Biino and colleagues, 2013, men aged 15 to 64
Men aged 15 to 64 · [4]
| Range | What the source calls it |
|---|---|
| below 141 thousand/µL | No name given |
| 141 to 362 thousand/µL | "reference interval" |
| above 362 thousand/µL | No name given |
The 2.5th to 97.5th percentiles in 40,987 inhabitants of 7 Italian areas, 6 of them geographic isolates, after excluding people with cancers, liver disease or inherited low platelet conditions. Counts differed between areas, and the authors also give a wider interval that allows for this [4].
Italian population studies, proposed reference intervals, Biino and colleagues, 2013, men older than 64
Men older than 64 · [4]
| Range | What the source calls it |
|---|---|
| below 122 thousand/µL | No name given |
| 122 to 350 thousand/µL | "reference interval" |
| above 350 thousand/µL | No name given |
Derived the same way. The authors report that the count in old age was 35% lower in men than in early infancy [4].
Italian population studies, proposed reference intervals, Biino and colleagues, 2013, women aged 15 to 64
Women aged 15 to 64 · [4]
| Range | What the source calls it |
|---|---|
| below 156 thousand/µL | No name given |
| 156 to 405 thousand/µL | "reference interval" |
| above 405 thousand/µL | No name given |
Derived the same way. From age 15, women had more platelets than men (a mean of 264 against 238 thousand/µL at ages 15 to 64) [4].
Italian population studies, proposed reference intervals, Biino and colleagues, 2013, women older than 64
Women older than 64 · [4]
| Range | What the source calls it |
|---|---|
| below 140 thousand/µL | No name given |
| 140 to 379 thousand/µL | "reference interval" |
| above 379 thousand/µL | No name given |
Derived the same way. The authors report that the count in old age was 25% lower in women than in early infancy [4].
Italian population studies, proposed reference intervals, Biino and colleagues, 2013, children under 15
Boys and girls younger than 15 · [4]
| Range | What the source calls it |
|---|---|
| below 176 thousand/µL | No name given |
| 176 to 452 thousand/µL | "reference interval" |
| above 452 thousand/µL | No name given |
Derived the same way from 1,702 children. The count did not differ between boys and girls under 15, so one interval is given [4].
World Health Organization classification of blood cancers, 2016, essential thrombocythemia criterion
Adults being assessed for essential thrombocythemia · [5]
| Range | What the source calls it |
|---|---|
| below 450 thousand/µL | No name given |
| 450 or above thousand/µL | "major criterion" |
One of four major criteria for diagnosing essential thrombocythemia, a bone marrow disorder. The others are a bone marrow biopsy finding, not meeting the criteria for related disorders, and a mutation in the JAK2, CALR or MPL gene, so a count at or above the threshold is not a diagnosis. The minor criterion is a clonal marker or the absence of evidence that the high count is a reaction to something else [5].
Reese and colleagues, platelet counts in pregnancy, 2018
Women with uncomplicated pregnancies · [6]
| Range | What the source calls it |
|---|---|
| below 150 thousand/µL | "gestational thrombocytopenia" |
| 150 or above thousand/µL | No name given |
The authors report that a count below 150 in an uncomplicated pregnancy is described as gestational thrombocytopenia when no other cause is identified. In their study the mean count in the first trimester was 251 against 273 in nonpregnant women, and 9.9% of women with uncomplicated pregnancies were below 150 at delivery. Only 1.0% were ever below 100, and the authors conclude that a count below 100 points to a cause other than pregnancy. No upper cutoff is given [6].
What has been shown to move it
Shown to raise it1
Inflammation and white blood cells
Limited evidence: small company-funded trials found white blood cell counts shifted after damaging exercise with grounding. No study measured C-reactive protein or an inflammatory disease.
Compared with sham grounding [4][5]
The numbers and sources
- Effect
- On day 3 after exercise, neutrophils were higher in grounded than sham-grounded men (P = 0.05), and platelets rose significantly in the grounded group on days 2 to 4 [4]. White blood cell counts were among the measures that differed by 10% or more in the 8-person pilot [5]. A review by researchers holding shares in the sponsoring company states that grounding alters circulating neutrophils, lymphocytes and inflammatory factors [6].
- Population
- 32 healthy young men [4]. 8 healthy adults [5]. Studies summarized in a review [6].
- Sources
- [4], [5], [6]
- Caveats
- A higher neutrophil count is not a lower level of inflammation, and the trials did not say whether these shifts help or harm. The review's authors disclose contracts with and shares in the company sponsoring grounding research [6].
How it compares with the reference method
Mixed results1
Variation from one draw to the next in one person
Shown to vary about 7% from one draw to the next within the same person, in a pooled estimate from a European laboratory federation.
The numbers and sources
- Compared with
- The same person's results on repeated venous draws
- Effect
- The European Federation of Clinical Chemistry and Laboratory Medicine database gives a pooled within-person variation of 7.3% for the platelet count, with lower and upper limits of 6.6% and 10.0%, from 7 included estimates. Variation between people is 17.2% [13]. At a count of 250 thousand/µL, 7.3% is about 18 thousand/µL.
- Population
- Healthy adults in the studies the database pools [13].
- Sources
- [13]
- Caveats
- A summary across studies in healthy volunteers. The database states no threshold for agreement, so the result is given as numbers only [13].
Did not match the reference method1
Falsely low counts from platelet clumping in the tube
Case series: the EDTA in the collection tube makes platelets clump in an estimated 0.03% to 0.27% of outpatients, which gives a falsely low count.
The numbers and sources
- Compared with
- A count on blood collected or handled so that platelets do not clump
- Effect
- A review puts the prevalence of this artifact, called pseudothrombocytopenia, at around 0.03% to 0.27% of outpatients, rising to 15.3% of patients referred to a clinic for an isolated low platelet count [11]. In a series of 112 cases followed for an average of 5 years, it was unrelated to age, sex, any particular disease or drug, and was found in people with and without illness. Clumping persisted at body temperature and in citrate tubes in about 20% of cases [12].
- Population
- Studies summarized in a 2021 review [11]. 112 people with the artifact observed over 10 years by one group [12].
- Sources
- [11], [12]
- Caveats
- The review reports that an unrecognized artifact has led to unnecessary tests and treatment, including platelet transfusion [11]. Prevalence figures come mostly from retrospective studies.
What studies tie it to
Linked in research4
Death from any cause
Linked to more deaths at low counts in two European cohorts, and at counts above 300 thousand/µL in one of them.
The numbers and sources
- Effect
- In Danish adults with counts of 100 to 450 thousand/µL, the relationship with death was U-shaped, with more deaths below 175 or above 300. Against 201 to 250, a count of 301 to 450 had an adjusted hazard ratio for death of 1.42 (95% CI 1.06 to 1.90) [7]. In Italian adults, a count under the lower limit for age and sex had a hazard ratio of 1.92 (1.38 to 2.67) for death from any cause, 1.77 (1.03 to 3.05) for cancer death and 3.16 (1.84 to 5.42) for deaths that were neither cardiovascular nor cancer. A count over the upper limit was not associated with any cause of death [8].
- Population
- 21,252 adults aged 20 and older in a Danish general population study [7]. 21,563 adults, mean age 55.6, in the Moli-sani study, 1,130 deaths over a median 8.2 years [8].
- Sources
- [7], [8]
- Caveats
- Observational. The two cohorts disagree about counts toward the high end. In the Italian study 87.7% of the low counts were still above 100 thousand/µL [8]. An illness that alters the platelet count before death cannot be ruled out.
Cancer
Limited evidence: one English cohort found cancer within a year in 11.6% of men and 6.2% of women aged 40 and older with a count above 400.
The numbers and sources
- Effect
- Among people aged 40 and older with a platelet count above 400 thousand/µL, 11.6% of men (95% CI 11.0 to 12.3) and 6.2% of women (5.9 to 6.5) were diagnosed with cancer within 1 year, against 4.1% of men and 2.2% of women with a count in the usual range. With a second raised count within 6 months the figures were 18.1% and 10.1%. Lung and colorectal cancer were the cancers most often found [9]. In a Danish cohort a count of 100 to 200 went with more later cancer than 201 to 250 (hazard ratio 1.28, 95% CI 1.05 to 1.57) [7].
- Population
- 40,000 primary care patients aged 40 and older with a count above 400 and 10,000 matched patients without, from English records for 2000 to 2013 [9]. 21,252 Danish adults [7].
- Sources
- [9], [7]
- Caveats
- Observational, from primary care records of people who had a blood count taken, with cancer counted over the following year only [9]. The Danish finding points the other way, toward low-normal counts [7].
Heart attack, stroke and other artery disease
Limited evidence: one Danish cohort linked a count of 301 to 450 thousand/µL to 32% more cardiovascular disease than a count of 201 to 250.
The numbers and sources
- Effect
- The adjusted hazard ratio for a later heart attack, ischemic stroke or peripheral vascular disease was 1.32 (95% CI 1.03 to 1.69) at 301 to 450 thousand/µL against 201 to 250. A count of 100 to 200 was not associated with later bleeding or venous clots [7]. In an Italian cohort, counts outside the limits for age and sex were not related to cardiovascular death [8].
- Population
- 21,252 adults aged 20 and older in a Danish general population study, linked to national registers [7]. 21,563 Italian adults [8].
- Sources
- [7], [8]
- Caveats
- One cohort, observational, adjusted for age, sex, smoking, hemoglobin, white cell count, C-reactive protein and other illness. It does not show that the platelet count itself changes risk [7].
Bleeding in immune thrombocytopenia
Linked to bleeding in people with immune thrombocytopenia, with bleeding inside the skull in 1.4% of adults and 0.4% of children across pooled studies.
The numbers and sources
- Effect
- In a systematic review of prospective studies of immune thrombocytopenia, a condition of low platelet counts, the pooled proportion with bleeding inside the skull was 1.4% in adults (95% CI 0.9% to 2.1%) and 0.4% in children (0.2% to 0.7%). Other severe bleeding occurred in 9.6% of adults (4.1% to 17.1%) and 20.2% of children (10.0% to 32.9%) [10].
- Population
- 10,908 patients in 118 studies [10].
- Sources
- [10]
- Caveats
- These are people with a diagnosed platelet disorder, not people with a mildly low count on a routine test. The abstract does not break bleeding down by platelet count, and the studies defined severe bleeding in different ways [10].
Sources
- US Food and Drug Administration. 21 CFR 864.5200, Automated cell counter. Electronic Code of Federal Regulations. https://www.ecfr.gov/current/title-21/section-864.5200
- Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey 2017-2018 Laboratory Procedure Manual: Complete Blood Count, whole blood, Beckman Coulter DxH 800 analyzer. Performed by the NHANES Mobile Examination Center. https://wwwn.cdc.gov/nchs/data/nhanes/public/2017/labmethods/CBC-J-MET-508.pdf
- Nordin G, Mårtensson A, Swolin B, et al. A multicentre study of reference intervals for haemoglobin, basic blood cell counts and erythrocyte indices in the adult population of the Nordic countries. Scandinavian Journal of Clinical and Laboratory Investigation. 2004. https://doi.org/10.1080/00365510410002797
- Biino G, Santimone I, Minelli C, et al. Age- And Sex-Related Variations in Platelet Count in Italy: A Proposal of Reference Ranges Based on 40987 Subjects' Data. PLoS ONE. 2013. https://doi.org/10.1371/journal.pone.0054289
- Barbui T, Thiele J, Gisslinger H, et al. The 2016 WHO classification and diagnostic criteria for myeloproliferative neoplasms: document summary and in-depth discussion. Blood Cancer Journal. 2018. https://doi.org/10.1038/s41408-018-0054-y
- Reese JA, Peck JD, Deschamps DR, et al. Platelet Counts during Pregnancy. New England Journal of Medicine. 2018. https://doi.org/10.1056/NEJMoa1802897
- Vinholt PJ, Hvas AM, Frederiksen H, et al. Platelet count is associated with cardiovascular disease, cancer and mortality: A population-based cohort study. Thrombosis Research. 2016. https://doi.org/10.1016/j.thromres.2016.08.012
- Bonaccio M, Di Castelnuovo A, Costanzo S, et al. Age- and sex-based ranges of platelet count and cause-specific mortality risk in an adult general population: prospective findings from the Moli-sani study. Platelets. 2018. https://doi.org/10.1080/09537104.2017.1411584
- Bailey SE, Ukoumunne OC, Shephard EA, et al. Clinical relevance of thrombocytosis in primary care: a prospective cohort study of cancer incidence using English electronic medical records and cancer registry data. British Journal of General Practice. 2017. https://doi.org/10.3399/bjgp17X691109
- Neunert C, Noroozi N, Norman G, et al. Severe bleeding events in adults and children with primary immune thrombocytopenia: a systematic review. Journal of Thrombosis and Haemostasis. 2015. https://doi.org/10.1111/jth.12813
- Lardinois B, Favresse J, Chatelain B, et al. Pseudothrombocytopenia: A Review on Causes, Occurrence and Clinical Implications. Journal of Clinical Medicine. 2021. https://doi.org/10.3390/jcm10040594
- Bizzaro N. EDTA-dependent pseudothrombocytopenia: a clinical and epidemiological study of 112 cases, with 10-year follow-up. American Journal of Hematology. 1995. https://doi.org/10.1002/ajh.2830500206
- European Federation of Clinical Chemistry and Laboratory Medicine. EFLM Biological Variation Database, meta-analysis estimates, read 2026-11-13. https://biologicalvariation.eu/