Blood Journal's Impact Factor (JIF)

Blood (ASH Journal)’s Journal Impact Factor (JIF)

Blood's Journal Impact Factor (JIF) is the Clarivate-computed, journal-level citation ratio that Blood -- the flagship, weekly peer-reviewed journal of the American Society of Hematology (ASH) -- receives each year in the Journal Citation Reports (JCR): citations in the JCR data year to the journal's citable items from the two preceding years, divided by that item count. This entry is specifically about Blood the hematology journal (ISSN 0006-4971 print, 1528-0020 online), published continuously by ASH since 1946 -- not about the common noun 'blood' or any life-sciences journal with a similar-sounding title. Blood is indexed in Clarivate's Science Citation Index Expanded, which makes it JIF-eligible on the same mechanical basis as any other JCR-indexed title. Reported figures for Blood's current JIF diverge across sources: ASH's own hematology.org materials have cited a figure near 23.9, third-party JCR-tracking aggregators (BioxBio, JournalsInsights, journalmetrics.org) show figures in roughly the 20-24 range for recent releases, and one ASH-affiliated page referenced 21.0 tied to the 2023 JCR release. These differences most likely reflect different JCR release years and aggregator caching lag rather than disagreement about the underlying data -- the same pattern seen across most single-journal JIF pages. Treat any one number as time-stamped to a specific JCR release -- Clarivate updates JCR every June -- and confirm the current, release-dated figure directly against ashpublications.org/blood or jcr.clarivate.com before citing it formally.

ByCASRAI Editorial Board

· Last updated 4 Sept 2026

What the number actually measures

The JIF is a ratio: citations received in a given JCR data year to a journal’s citable items (original research articles and reviews) published in the two preceding years, divided by the number of those citable items. Blood (ISSN 0006-4971 print, 1528-0020 online) is indexed in Clarivate’s Science Citation Index Expanded and receives its own JIF computed the same mechanical way as every other JCR-indexed title — the formula does not vary by field, journal age, or publisher.

Blood’s Impact Factor in 2026: what the named sources actually say

CASRAI does not publish a figure for Blood, because no figure could be attributed to a named, dated source. The publisher’s own journal page (ashpublications.org/blood) returned HTTP 403 to every automated request CASRAI made on 23 August 2026, including with a full browser user-agent and cookie handling, so no publisher-stated figure could be read. Clarivate’s JCR is behind an institutional subscription. No third-party aggregator figure is repeated here.

How to get the number yourself. The authoritative source is Clarivate’s Journal Citation Reports, which sits behind an institutional Web of Science subscription — most university libraries provide it, and the lookup takes under a minute by ISSN. Clarivate’s free Master Journal List will confirm whether the journal is in the Web of Science Core Collection at all (a title that is not indexed there receives no Impact Factor), though it does not show the numeric score. CASRAI’s guide to looking up a journal’s Impact Factor walks through both steps.

What CASRAI could verify at source

ISSN: 0006-4971 (print), 1528-0020 (online) — Crossref journal record, checked 23 August 2026.
Publisher: American Society of Hematology (ASH) — Crossref journal record, checked 23 August 2026.
PubMed / MEDLINE: Currently indexed for MEDLINE; MEDLINE coverage v26n4, Oct. 1965-; also in Abridged Index Medicus — NLM Catalog record, checked 23 August 2026.
DOAJ: Not listed in DOAJ (subscription journal) — DOAJ API, checked 23 August 2026.
Journal Impact Factor: no figure is published on this page, because none could be attributed to a named, dated source — see the explanation above.

Blood’s Journal Impact Factor by JCR data year

Clarivate issues a new Journal Impact Factor for every indexed title each June, so the figure is a property of a data year rather than of the journal. The series below runs most recent first, with the source named against every row and the date CASRAI read it. Clarivate’s Journal Citation Reports is paywalled and CASRAI has not read it directly; rows attributed to a tracker are third-party readings of Clarivate’s release, not Clarivate’s own publication. Figures for the 2021 data year and earlier are shown to three decimal places because that is how Clarivate published them at the time; from the 2022 data year Clarivate rounds the JIF to one decimal place.

The 2025 figure is stated by the publishing society itself: the American Society of Hematology’s own site (hematology.org/publications) says “With an Impact Factor of 23.9, Blood is the most cited peer-reviewed publication in the field of hematology with over 168,000 citations in 2025.” ASH’s journal platform, ashpublications.org, was still returning HTTP 403 to CASRAI on 23 August 2026, so that figure could not also be read there. The longer series is from BioxBio (bioxbio.com/journal/BLOOD), a third-party JCR tracker, whose 2025 row gives 23.9 and 168,805 total cites. A further cross-check is wos-journal.info/journalid/131 (a third-party Web of Science tracker, confirmed on the page itself to carry ISSN 0006-4971). All were read on 23 August 2026.

JCR data year	Clarivate release	Journal Impact Factor	Attributed to, read 23 August 2026
2025	June 2026	23.9	hematology.org (ASH, the publishing society); BioxBio; wos-journal.info (all three agree)
2024	June 2025	23.1	BioxBio
2023	June 2024	21.0 (BioxBio) or 21.1 (Wikipedia) — see below	BioxBio; Wikipedia infobox (they disagree)
2022	June 2023	20.3	BioxBio
2021	June 2022	25.476	BioxBio
2020	June 2021	22.113	BioxBio
2019	June 2020	17.543	BioxBio
2018	June 2019	16.562	BioxBio
2017	June 2018	15.132	BioxBio
2016	June 2017	13.164	BioxBio
2015	June 2016	11.847	BioxBio
2014	June 2015	10.452	BioxBio
2013	June 2014	9.775	BioxBio
2012	June 2013	9.060	BioxBio

Category and quartile

Clarivate assigns Blood to the Web of Science category Hematology (Science Citation Index Expanded). For the current release, wos-journal.info gives its percentage rank within that category as 98.1% (read 23 August 2026). On wos-journal.info’s own stated scale — Q1 is better than 75% of the journals in the category, Q2 better than 50%, Q3 better than 25%, Q4 the rest — 98.1% places it in Q1. CASRAI has not read the quartile in Clarivate’s Journal Citation Reports itself, so treat it as a tracker-derived reading of the category position, not as a quartile quoted from JCR. The 5-year Impact Factor, a separate figure that widens the citation window from two years to five, is 20 for the current release, per wos-journal.info.

Sources disagree on the 2023 data year, so here are both. BioxBio gives 21.0 and the Wikipedia infobox for the journal gives 21.1, both for the 2023 JCR data year. CASRAI cannot resolve the 0.1 difference against a primary Clarivate source, and Clarivate’s JCR is paywalled, so both readings are shown rather than one being picked.

This resolves the gap noted above: at the time of the earlier revision no figure for Blood could be attributed to a named, dated source, because ashpublications.org was blocked. ASH’s society site states one, so a figure can now be given — sourced to ASH, not to Clarivate directly.

Re-check any row above against the source named beside it before quoting it in a CV, tenure file, grant application or funder report, and say which JCR data year you mean. A rising or falling series says nothing about any individual paper published in a given year — the JIF is a journal-level average, for the reasons set out elsewhere on this page.

Why the figure matters in hematology specifically, and what it doesn’t tell you

Within hematology, Blood’s JIF is often used informally as a benchmark against comparable subspecialty journals such as Leukemia or the American Journal of Hematology, and against Blood’s own sister publication, Blood Advances. A high JIF reflects that Blood’s published articles are, on average, cited frequently within the two-year citation window — it does not mean every individual article is highly cited, nor that a specific paper published in Blood is inherently more rigorous than a comparable paper published elsewhere. Per DORA (San Francisco Declaration on Research Assessment) and CoARA’s responsible-assessment guidance, journal-level metrics like the JIF should not substitute for evaluating the actual content of a specific paper, or the contributions of a specific researcher, in hiring, promotion, or funding decisions.

Related terms

Journal Impact Factor (JIF) — the general metric this page illustrates with one journal’s current figure.
Journal Citation Reports (JCR) — the Clarivate product that publishes the JIF annually.
New England Journal of Medicine’s Journal Impact Factor (JIF) — another single-journal illustrative instance, for cross-field comparison.
Cell’s Journal Impact Factor (JIF) — another single-journal illustrative instance.
CiteScore — Elsevier/Scopus’s competing journal-level metric for the same journal, with a different window and denominator.
DORA (San Francisco Declaration on Research Assessment) — the reform commitment behind the over-reliance caveat above.

Use in your systems

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