ISTH Bleeding Assessment Tool (ISTH-BAT)
The ISTH-BAT is a structured bleeding-history questionnaire that assigns bleeding scores across predefined bleeding symptoms and procedures. [1] A cumulative bleeding score is compared with sex- and age-specific cutoffs to screen for an underlying congenital bleeding disorder. [1], [2]
Scoring domains included in the ISTH-BAT
The standardized ISTH-BAT symptom domains use a 0 to 3 ordinal scoring scale (with certain domains using a restricted 0–1 scoring distinction). [1] The domains shown in the summarized score table include: [1]
- Epistaxis. [1]
- Cutaneous symptoms (bruising). [1]
- Bleeding from minor wounds. [1]
- Oral cavity symptoms. [1]
- Gastrointestinal bleeding. [1]
- Hematuria. [1]
- Tooth extraction. [1]
- Surgery-related bleeding. [1]
- Menorrhagia. [1]
- Missed work/school (bleeding-related impact). [1]
- Postpartum hemorrhage. [1]
- Muscle hematomas. [1]
- Hemarthrosis. [1]
- Central nervous system bleeding. [1]
- Other bleeding. [1]
ISTH-BAT symptom scoring table (0–3)
The ISTH-BAT scoring table below shows the descriptor for each score category per symptom domain. [1]
- Epistaxis: score 0 = none/trivial; score 1 = >5 per year or lasting >10 minutes; score 2 = consultation only; score 3 = packing/cauterization/antifibrinolytic therapy. [1]
- Cutaneous symptoms (bruising): score 0 = none/trivial; score 1 = at least five bruises (>1 cm) in exposed areas; score 2 = consultation only; score 3 = extensive. [1]
- Bleeding from minor wounds: score 0 = none/trivial; score 1 = >5 per year or lasting >10 minutes; score 2 = consultation only; score 3 = surgical hemostasis. [1]
- Oral cavity symptoms: score 0 = none/trivial; score 1 = present; score 2 = consultation only; score 3 = surgical hemostasis or antifibrinolytic therapy. [1]
- Gastrointestinal bleeding: score 0 = none/trivial; score 1 = present (not associated with ulcer/portal hypertension/hemorrhoids/angiodysplasia); score 2 = consultation only; score 3 = surgical hemostasis or antifibrinolytic therapy. [1]
- Hematuria: score 0 = none/trivial; score 1 = present (macroscopic); score 2 = consultation only; score 3 = surgical hemostasis or iron therapy. [1]
- Tooth extraction: score 0 = none/trivial; score 1 = reported in ≤25% of all procedures with no intervention; score 2 = reported in >25% of all procedures with no intervention; score 3 = resuturing or packing. [1]
- Surgery: score 0 = none/trivial; score 1 = reported in ≤25% of procedures with no intervention; score 2 = reported in >25% of procedures with no intervention; score 3 = surgical hemostasis or antifibrinolytic therapy. [1]
- Menorrhagia: score 0 = none/trivial; score 1 = consultation only or increased pad use (>every 2 hours), clotting/flooding, or pictorial blood loss assessment chart score >100; score 2 = missed work/school >2 times per year with antifibrinolytic/hormone/iron therapy; score 3 = combined antifibrinolytic and hormone therapy or present since menarche and lasting >12 months. [1]
- Postpartum hemorrhage: score 0 = none/trivial; score 1 = consultation only or oxytocin use or lochia lasting >6 weeks; score 2 = iron or antifibrinolytic therapy; score 3 = blood transfusion/replacement therapy/desmopressin or anesthesia evaluation and/or uterine balloon/packing to tamponade uterus. [1]
- Muscle hematomas: score 0 = never; score 1 = post-trauma with no therapy; score 2 = spontaneous or traumatic requiring desmopressin or replacement therapy; score 3 = (not shown as separate descriptor in the summarized excerpt beyond the 0–2 gradations for this row). [1]
- Hemarthrosis: score 0 = never; score 1 = post-trauma with no therapy; score 2 = spontaneous or traumatic requiring desmopressin or replacement therapy; score 3 = (not shown as separate descriptor in the summarized excerpt beyond the 0–2 gradations for this row). [1]
- Central nervous system bleeding: score 0 = never; score 3 = subdural with any intervention. [1]
- Other bleeding: score 0 = none/trivial; score 1 = present; score 2 = consultation only; score 3 = surgical hemostasis or antifibrinolytic therapy. [1]
Key scoring clarifications used in the table
The distinction between score 0 and score 1 is clinically important because score 1 indicates that the symptom is judged present in history but does not meet criteria for score 2 or higher. [1] A “consultation only” score requires patient medical evaluation with referral to a specialist or offer of detailed laboratory investigation. [1] For tooth extraction and surgery, the score thresholds use the proportion of procedures with bleeding. [1] A pictorial blood loss assessment chart is referenced for menorrhagia scoring when already available at the time of collection. [1]
ISTH-BAT screening cutoffs reported for abnormal bleeding
Normal-score cutoffs reported from the merging project are: [2]
- Adult males: abnormal threshold ≥4. [2]
- Adult females: abnormal threshold ≥6. [2]
- Children: abnormal threshold ≥3. [2] A primary care summary article also reports normal cutoff values as 3 for men, 5 for women, and 2 for children. [1]
Use context and practical administration
The ISTH-BAT is used during initial evaluation of patients with suspected bleeding disorders. [1] The tool is administered by a clinician or trained personnel and takes approximately 20 minutes. [1]
Source references for the scoring sheet content
A published clinical evaluation review provides the ISTH-BAT table of symptom domains and score descriptors in a condensed format. [1] Cutoff thresholds are supported by analysis of adult and pediatric distributions from the merging project. [2]
Links to the full ISTH-BAT document
The full ISTH-BAT instrument is described as available for free via ISTH resources, but the complete PDF content could not be retrieved directly from the ISTH hosting endpoint in this environment. [1]