Hematocrit by age and sex
Each bar runs from the 5th to the 95th percentile, the darker part from the 25th to the 75th, and the tick is the median. Not a reference range or a target.
The percentiles as a table
| Sex | Age | 5th | 25th | Median | 75th | 95th | n | Cycle / source |
|---|---|---|---|---|---|---|---|---|
| All | 20-39 | 36.1 | 39.8 | 42.6 | 45.1 | 48.6 | 1,457 | NHANES 2017-2018 |
| All | 40-59 | 36.3 | 39.9 | 42.5 | 45.1 | 48.3 | 1,584 | NHANES 2017-2018 |
| All | 60+ | 35.1 | 39.2 | 41.7 | 44.2 | 48.2 | 1,940 | NHANES 2017-2018 |
| All | all | 35.8 | 39.7 | 42.3 | 44.8 | 48.4 | 4,981 | NHANES 2017-2018 |
| Men | 20-39 | 40.9 | 43.2 | 44.8 | 46.7 | 49.8 | 698 | NHANES 2017-2018 |
| Men | 40-59 | 39.7 | 42.7 | 44.7 | 46.4 | 49.6 | 740 | NHANES 2017-2018 |
| Men | 60+ | 35.9 | 40.9 | 43.3 | 46.0 | 49.6 | 981 | NHANES 2017-2018 |
| Men | all | 39.0 | 42.5 | 44.3 | 46.5 | 49.7 | 2,419 | NHANES 2017-2018 |
| Women | 20-39 | 35.0 | 38.1 | 40.0 | 41.7 | 43.9 | 759 | NHANES 2017-2018 |
| Women | 40-59 | 34.8 | 38.5 | 40.3 | 42.5 | 45.1 | 844 | NHANES 2017-2018 |
| Women | 60+ | 34.9 | 38.5 | 40.7 | 42.8 | 45.8 | 959 | NHANES 2017-2018 |
| Women | all | 34.9 | 38.3 | 40.3 | 42.2 | 45.1 | 2,562 | NHANES 2017-2018 |
What studies found when this marker was changed
They describe what happened in those study groups, not a recommendation. See all catalogued interventions.
Measured changes in Hematocrit, study by study
5 effects with a numeric size, each from one study arm: the dot is the reported change, the line its 95% interval where one was given. Study results in the groups studied, not predictions for a person.
| Type | Intervention | Reported effect | Evidence | Source |
|---|---|---|---|---|
| clinical | Delaying umbilical cord clamping by at least 30 seconds (most trials >=60 s) at birth of infants <37 weeks' gestation (meta-analysis of 18 RCTs) | Raises peak neonatal hematocrit by 2.73 percentage points (95% CI 1.94-3.52) and reduces transfusion by 10%; hospital mortality RR 0.68 | meta-analysis | Fogarty M, et al. American journal of obstetrics and gynecology. 2018. Delayed… |
| environmental | Sleeping under pyrethroid insecticide-treated bed nets or curtains in malaria-endemic areas, compared with no nets (Cochrane review, trials 1987-2001) | Mean packed cell volume 1.29 percentage points higher (95% CI 0.42-2.16) with ITNs vs no nets (high-certainty evidence) | meta-analysis | Pryce J, et al. The Cochrane database of systematic reviews. 2018… |
| pharmacologic | Subcutaneous rusfertide during a 28-week dose-finding period in patients with phlebotomy-dependent polycythemia vera (REVIVE part 1) | Mean maximum hematocrit 44.5% during 28 weeks of rusfertide vs 50.0% in the 28 weeks before treatment; phlebotomies 8.7 -> 0.6 per year | RCT | Kremyanskaya M, et al. The New England journal of medicine. 2024. Rusfertide, a… |
| pharmacologic | Oral oxymetholone for anaemia in adults with chronic kidney disease (Cochrane review; 1 study, 24 participants) | Haematocrit 27.10 percentage points higher (95% CI 26.49-27.71) with oxymetholone (1 study, 24 participants); haemoglobin +1.90 g/dL | meta-analysis | Yang Q, et al. The Cochrane database of systematic reviews. 2014. Androgens for… |
What else moves this marker
They describe those study groups, not an individual, and an association is not a cause.
Genetic predisposition
| What | Effect on the marker | Comparison · population | Source |
|---|---|---|---|
| ↑ CHRNA3 rs1051730 T allele (smoking-intensity variant), current smokers · percent difference in hematocrit per T allele in current smokers | +0.34 percent difference per T allele per allele (95% CI 0.17 to 0.5) | per additional T allele, current smokers · White Danes aged 20-100, Copenhagen General Population Study (17,852 current smokers) | mendelian randomization · PMID 30866659 |
Environmental and occupational exposures
| What | Effect on the marker | Comparison · population | Source |
|---|---|---|---|
| ↑ Current cigarette smoking · current smokers vs non-smokers | SMD +0.53 (95% CI 0.42 to 0.64) | current smokers vs non-smokers · 92 studies including GESUS | meta analysis · PMID 31875952 |
| ↓ Genetically predicted smoking initiation · 113-SNP instrument for smoking initiation | -0.06 SD 113-SNP instrument for smoking initiation (95% CI -0.09 to -0.03) | per unit genetic liability to smoking initiation · GWAS summary statistics (blood cell traits) | mendelian randomization · PMID 39236005 |
Sources
- See the catalogue entry in the research dashboard.
Related markers: Absolute Lymphocyte Count · Absolute Neutrophil Count · Basophil Count · Eosinophil Count · Hemoglobin Concentration · Immature Reticulocyte Fraction · Lymphocyte Percentage · Mean Corpuscular Volume (MCV)