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January 2023

Q. My patient is anaemic, what test should I request next?

A. Anaemia is usually defined by laboratory criteria; those patients with a haemoglobin concentration two standard deviations below the mean, i.e. <130g/L for men and <120g/L for women as defined by WHO. Patients with even mild anaemia have poorer outcomes in many domains, and anaemia will tend to have a more profound impact in times of physiological or pathological stress. As clinicians we recognise the impact anaemia can have on our patients, and we wish to identify the cause of anaemia so that we can help, however the myriad of causes for anaemia, alongside a shifting landscape of tests that are available can make it difficult to formulate a diagnostic plan.

The Manchester Anaemia Guide was written with this problem in mind; the aim was to form clear pathways of investigation for adult patients with anaemia and highlighting which patients are likely to benefit from a referral to haematology

Q. My patient is to undergo major surgery, is there anything I can do to optimise their outcome?

A. We know that anaemia is a common independent risk factor for operative complications and death. It is therefore a priority to recognise anaemia early, identify the cause, and instigate appropriate treatment to mitigate the negative impact of anaemia on their surgical care.

As part of their pre-operative assessment patients will be investigated for anaemia and if iron deficiency is identified in a patient listed for an urgent procedure, an iron infusion will be organised. In other cases, where surgery is non-urgent, the team will write to the patient’s general practitioner asking them to initiate supplementation. This is also the case for folate or B12 deficiency.

It is important to be aware that the definition of pre-operative anaemia differs from the usual ‘normal’ range; e.g women with haemoglobin <130g/L are defined as having pre-operative anaemia. These patients will still benefit from measures to increase their haemoglobin despite it apparently sitting in the ‘normal’ range.

Clinicians should also be aware that laboratory reference ranges for ferritin and other measures of iron stores maybe misleading. Many patients have low level chronic inflammation causing ferritin to be elevated even in the context of iron deficiency. Transferrin saturation (TSAT) is a useful measurement, with TSAT <16% supporting a diagnosis of iron deficiency, even if the ferritin is in the normal range. Note that serum iron is used to calculate TSAT but in itself is not a useful marker for assessing iron stores.

Given the current strain on waiting lists for operative procedures, it would be advantageous for GPs to screen for anaemia at the point of referral to the surgeons, so that replacement of iron, folate and B12 can be started in good time.

Replacing iron preoperatively has been demonstrated to reduce peri-operative transfusions. Avoiding the risks of transfusion is better for patients, and in the context of recent national blood shortages there is also to the wider community of avoiding unnecessary transfusions where possible.

Q. My patient has an abnormal blood count/big spleen/myeloma screen/high ferritin, what should I do next?

A. Much like anaemia, abnormalities in haematological blood tests such as the full blood count can be challenging to interpret. Clinicians know that on many occasions, tests are transiently abnormal because of an acute event, or chronically deranged due to long term conditions. Equally, abnormal tests may be a sign of serious pathology including malignancy.

To assist clinicians in determining the right way forward, the MFT Haematology GP Pathway Guide was created. In much the same way as the anaemia guide, the aim is form clear pathways of investigation and highlight when and how patients might need to be seen by a haematologist.