Assessment overview
How this assessment usually works
Blood-system impairment uses AMA5 Chapter 9 with NSW Chapter 12 modifications. The assessor must identify the applicable disorder, stable symptoms, laboratory and treatment evidence, then separately assess any permanent end-organ effect.
For haematopoietic system, the assessor gives a medical opinion about permanent impairment under the NSW workers compensation guidelines; the assessor does not decide legal liability. Once the body-system method and percentage are understood, separate advice may be needed about Section 66 compensation, weekly payments, medical-expense time limits or work injury damages.
Injuries and diagnoses assessed in this body system
The referral and report should identify the accepted diagnosis precisely. Similar symptoms can use different assessment methods depending on the injured structure.
- anaemia and transfusion-dependent blood disorders
- polycythaemia, myelofibrosis and white-blood-cell disease
- haemorrhagic, platelet and thrombotic disorders requiring ongoing treatment
- functional asplenia and separately rateable end-organ effects caused by a blood disorder
When a permanent impairment assessment can occur
For haematopoietic system, assessment should occur only after maximum medical improvement (MMI). NSW Guidelines paragraph 1.15 describes a condition that is well stabilised and unlikely to change substantially during the next year, with or without treatment.
For haematopoietic system, if adequate treatment or rehabilitation could materially change the impairment, paragraph 1.16 says the assessment should be deferred. The report should explain why the timing is appropriate.
For haematopoietic system, serial laboratory and treatment evidence should show a stable pattern. An acute blood-count change during infection, surgery or another temporary illness is not by itself a permanent impairment baseline.
The NSW and AMA5 assessment method
The NSW Workers Compensation Guidelines prevail over AMA5 wherever the two differ. The method is a medical assessment framework, not a self-scoring exercise.
NSW Guidelines Chapter 12 applies AMA5 Chapter 9 with replacement and modified criteria. NSW Table 12.1 replaces AMA5 Table 9-2 for anaemia.
Table 12.1 uses four classes based on symptoms, pre-transfusion haemoglobin and transfusion need. The haemoglobin levels are indicators, not instructions to allow a worker to reach an unsafe level.
The assessor must state both the class and a precise WPI, using clinical judgment. Comorbidity may affect whether transfusion actually occurs, so class selection must explain the clinical need rather than mechanically reading one laboratory number.
Haemorrhagic, platelet and thrombotic disorders use AMA5 Table 9-4 with the NSW Class 3 and Class 4 criteria. Treatment dependence and the need for occasional assistance or continuous care are central to those higher classes.
End-organ impairment caused by the blood disorder is assessed under its own body-system chapter and combined with the haematopoietic WPI only where permitted.
What the assessor actually measures
For haematopoietic system, the percentage should be traceable to relevant, stable and reproducible findings.
- stable symptoms and serial full blood count, haemoglobin and other disorder-specific laboratory results
- pre-transfusion haemoglobin and the frequency and volume of transfusion where relevant
- venesection, anticoagulation, replacement or other continuing treatment and its clinical consequences
- bleeding, thrombotic or platelet events and the level of assistance required in daily activities
- objective end-organ dysfunction assessed under the appropriate body-system chapter
How the measurements are converted to WPI
NSW Table 12.1 Class 1 is 0-10% WPI: no symptoms, haemoglobin 100-120 g/L and no transfusion. Class 2 is 11-30%: minimal symptoms, haemoglobin 80-100 g/L and no transfusion.
Class 3 is 31-70% WPI: moderate to marked symptoms, indicative pre-transfusion haemoglobin 50-80 g/L and 2-3 units generally required every 4-6 weeks. Class 4 is 71-100%: similar symptom and haemoglobin criteria with 2-3 units generally required every two weeks.
The assessor identifies a precise WPI within the class from the complete clinical circumstances and explains any departure from the indicative transfusion pattern.
Functional asplenia is 3% WPI and is combined with another permitted WPI through the Combined Values Chart.
Verified category and table examples
These short examples show how the published method works. They do not predict an individual assessment.
| Finding or category | Published value or method | Source |
|---|---|---|
| Anaemia Class 1 | 0-10% WPI | NSW Guidelines Table 12.1 |
| Anaemia Class 2 | 11-30% WPI | NSW Guidelines Table 12.1 |
| Anaemia Class 3 | 31-70% WPI | NSW Guidelines Table 12.1 |
| Anaemia Class 4 | 71-100% WPI | NSW Guidelines Table 12.1 |
| Functional asplenia | 3% WPI | NSW Guidelines paragraph 12.8 |
Worked illustrations
How the assessment method can operate
These paraphrased illustrations explain the published method. They are not estimates of another worker's WPI.
Illustration: an anaemia class is a range, not a fixed diagnosis value
Assumed findings: A worker has stable accepted anaemia with minimal symptoms, serial haemoglobin around 90 g/L and no transfusion requirement. The specialist explains why the findings are stable and attributable to the accepted condition.
Method and arithmetic: Those assumed findings fit NSW Table 12.1 Class 2, a range of 11-30% WPI. The assessor must use clinical judgment to select and explain a precise point within that range; 90 g/L does not mechanically map to one percentage.
What the illustration shows: A single low result during temporary illness would not establish the same class, and a transfusion prevented by comorbidity requires reasoned clinical treatment. This paraphrased illustration is not an estimate.
Method source: NSW Guidelines paragraphs 12.3-12.7 and Table 12.1
Illustration: a blood disorder and end-organ loss use separate methods
Assumed findings: A stable accepted haematopoietic disorder causes a separately verified permanent organ impairment.
Method and arithmetic: The blood-system class is assessed under NSW Chapter 12. The organ impairment is assessed under its own chapter, checked for overlap and combined through the Combined Values Chart if permitted.
What the illustration shows: The values are not added arithmetically and the same functional consequence is not rated twice. This is an illustration only.
Method source: NSW Guidelines paragraph 12.2; AMA5 Combined Values Chart
What does not establish WPI by itself
These matters can remain medically and practically important, but they do not replace the measurements or category requirements in the applicable method.
- one abnormal blood result without a stable diagnosed disorder
- the diagnosis name without symptoms, treatment, serial laboratory and class evidence
- the top of a broad class selected without clinical reasoning
- transfusion frequency read mechanically without considering documented medical contraindication or need
- an end-organ value added arithmetically or the same consequence counted twice
Evidence checklist
The assessor should receive enough material to test the accepted injury, stability, measurable impairment and any deduction.
- the accepted injury or disease description and any insurer liability decisions
- contemporaneous GP, hospital and treating-specialist records
- relevant investigations, pathology, procedure reports and treatment history
- earlier impairment assessments and evidence about any pre-existing impairment
- a current clinical opinion explaining stability and whether material improvement remains likely
- haematology reports and serial laboratory results showing the stable pattern
- pre-transfusion results, transfusion, venesection, anticoagulation and treatment schedules
- hospital records for bleeding, thrombotic or other material episodes
- specialist reports and WPI calculations for any end-organ consequence
Common insurer or report disputes
A disagreement about haematopoietic system WPI may concern the accepted diagnosis, the body-system findings, the selected method, a deduction or the way another impairment was handled. The report should identify the disputed step rather than leave the percentage unexplained.
- one abnormal result is treated as a permanent class
- the selected point within a broad class is unexplained
- end-organ impairment is omitted or duplicated
- combination uses ordinary addition instead of the chart
Sources for this assessment guide
The public NSW Guidelines control where they modify AMA5. AMA5 table references below identify the method without reproducing the proprietary table in full.
- NSW Guidelines Chapter 12, paragraphs 12.1-12.12 and Table 12.1: anaemia classes, clinical judgment, asplenia, platelet, haemorrhagic, thrombotic and end-organ rules.
- AMA5 Chapter 9, especially Table 9-4: haemorrhagic, platelet and thrombotic class framework, subject to NSW modifications.
- AMA5 Combined Values Chart, pp 604-606: permitted combination of distinct WPI values.
Questions to ask when the report comes back
These questions help identify whether the report explains its method and evidence. They do not replace medical or legal advice about the particular assessment.
- Which NSW or AMA5 class applies?
- What laboratory and treatment evidence supports it?
- Why was the specific WPI within the class selected?
- Was end-organ WPI assessed and combined correctly?
How this connects to thresholds and strategy
In a haematopoietic system claim, SIRA's permanent impairment thresholds must be applied to the accepted injury and the supported body-system percentage. The general thresholds are 11% or more permanent impairment for physical injury and 15% or more for primary psychological injury; secondary psychological injury is treated differently. A threshold is an eligibility checkpoint, not a promised payment.
A low haematopoietic system WPI opinion may affect weekly-payment planning, treatment time-limit issues, dispute posture and whether work injury damages threshold advice is required. Before the opinion is relied on, check the relevant measurements, body-system method, deduction and practical consequences.
Questions workers often ask
Does an anaemia diagnosis have one fixed WPI?
No. NSW Table 12.1 contains classes and ranges. The assessor states a specific WPI using symptoms, laboratory findings, transfusion needs and clinical judgment.
How is functional asplenia assessed?
NSW paragraph 12.8 assigns 3% WPI and requires combination with any other permitted impairment.
How are end-organ effects handled?
They are assessed under the relevant body-system chapter and combined with blood-system WPI only where permitted.
Is one blood test enough?
Usually not. The report should address stable diagnosis, serial findings, treatment and the criteria required by the applicable class.
General information only
This information is general in nature and is not legal advice. You should obtain advice about your own circumstances before relying on a WPI percentage, accepting a lump sum offer, or responding to an insurer decision.
Reviewed by NSW Work Injury Claims - a branch of Stephen Young Lawyers.
Related injury and impairment pages
Need a WPI assessment checked?
If the percentage does not match the accepted injury, treatment history, imaging, surgery, work duties or current restrictions, get the report checked before accepting the insurer position.