Individuals of sub-Saharan African descent with ferroportin Q248H are more likely to be diagnosed with African iron overload than individual without ferroportin mutation because individuals with ferroportin Q248H have elevated level of serum ferritin concentration. Individuals of African descent should also avoid drinking traditional beer.

Elevation in ferritin concentration without elevation in transferrin saturation does not rule out an iron overload disorder. This combination can be observed in loss-of-function ferroportin mutation and in aceruloplasminemia. Elevated level of ferritin concentration can be observed in acute or chronic inflammatory process without pathologic iron overload.

Ferritin level above 200 ng/mL (449 pmol/L) in women or 300 ng/mL (674 pmol/L) in men who have no signs of inflammatory disease need additional testing. Transferrin saturation above normal range in male and female also need additional testing.

Chemical evidence of tissue vitamin C deficiency and mild to moderate liver dysfunction are likely to be seen in individuals with African iron overload. Elevation in Gamma-glutamyl transpeptidase can be used as a marker for abnormalities in liver function.

The severity of iron overload can be determined and monitored using a combination of tests. Measurement of serum ferritin indicates for total body iron overload. Liver biopsy measures the iron concentration of liver. It provides the microscopic examination of the liver. Measurement of serum hepcidin levels may be useful in diagnostic for iron overload. MRI can detect the degree of magnetic disruption due to iron accumulation. MRI can measure iron accumulation within the heart, liver, and pituitary. Accumulation of iron in a single organ does not provide proper representation of the total body iron overload.

It is important to use both the imaging techniques and serum ferritin level as indicators to start the therapy of iron overload. Serum level and the imaging techniques can be used as markers for treatment progress.

There exist other causes of excess iron accumulation, which have to be considered before haemochromatosis is diagnosed.

- African iron overload, formerly known as Bantu siderosis, was first observed among people of African descent in Southern Africa. Originally, this was blamed on ungalvanised barrels used to store home-made beer, which led to increased oxidation and increased iron levels in the beer. Further investigation has shown that only some people drinking this sort of beer get an iron overload syndrome, and that a similar syndrome occurred in people of African descent who have had no contact with this kind of beer ("e.g.," African Americans). This led investigators to the discovery of a gene polymorphism in the gene for ferroportin which predisposes some people of African descent to iron overload.

- Transfusion haemosiderosis is the accumulation of iron, mainly in the liver, in patients who receive frequent blood transfusions (such as those with thalassaemia).

- Dyserythropoeisis, also known as myelodysplastic syndrome, is a disorder in the production of red blood cells. This leads to increased iron recycling from the bone marrow and accumulation in the liver.

There is no consensus on how to treat LID but one of the options is to treat it as an iron-deficiency anemia with ferrous sulfate (Iron(II) sulfate) at a dose of 100 mg x day in two doses (one at breakfast and the other at dinner) or 3 mg x Kg x day in children (also in two doses) during two or three months. The ideal would be to increase the deposits of body iron, measured as levels of ferritin in serum, trying to achieve a ferritin value between 30 and 100 ng/mL. Another clinical study has shown an increase of ferritin levels in those taking iron compared with others receiving a placebo from persons with LID. With ferritin levels higher than 100 ng/mL an increase in infections, etc. has been reported. Another way to treat LID is with an iron rich diet and in addition ascorbic acid or Vitamin C, contained in many types of fruits as oranges, kiwifruits, etc. that will increase 2 to 5-fold iron absorption.

First degree relatives of those with primary haemochromatosis should be screened to determine if they are a carrier or if they could develop the disease. This can allow preventive measures to be taken.

Screening the general population is not recommended.

Serum transferrin and transferrin saturation are commonly used as screening for haemochromatosis. Transferrin binds iron and is responsible for iron transport in the blood. Measuring transferrin provides a crude measure of iron stores in the body. Fasting transferrin saturation values in excess of 45% for males or 35% in premenopausal women (i.e. 300 ng/L in males and 200 ng/L in females) are recognized as a threshold for further evaluation of haemochromatosis. Transferrin saturation greater than 62% is suggestive of homozygosity for mutations in the HFE gene.

Serum Ferritin: Ferritin, a protein synthesized by the liver is the primary form of iron storage within cells and tissues. Measuring ferritin provides another crude estimate of whole body iron stores though many conditions, particularly inflammation (but also chronic alcohol consumption, non-alcoholic fatty liver disease and others), can elevate serum ferritin - which can account for up to 90% of cases where elevated levels are observed. Normal values for males are 12–300 ng/ml (nanograms per millilitre) and for female, 12–150 ng/ml. Serum ferritin in excess of 1000 nanograms per millilitre of blood is almost always attributable to haemochromatosis.

Other blood tests routinely performed: blood count, renal function, liver enzymes, electrolytes, glucose (and/or an oral glucose tolerance test (OGTT)).

As always, laboratory values have to be interpreted with the lab's reference values in mind and considering all aspects of the individual clinical situation.

Serum ferritin can be elevated in inflammatory conditions; so a normal serum ferritin may not always exclude iron deficiency, and the utility is improved by taking a concurrent C-reactive protein (CRP). The level of serum ferritin that is viewed as "high" depends on the condition. For example, in inflammatory bowel disease the threshold is 100, where as in chronic heart failure (CHF) the levels are 200.

There are several methods available for diagnosing and monitoring iron loading including:

- Serum ferritin: In males and postmenopausal females, a serum ferritin value of over 300 ng/mL (670 pmol/L) indicates iron overload. In premenopausal females, a serum ferritin value of over 150 or 200 ng/mL (330 or 440 pmol/L) indicates iron overload.

- Liver biopsy

- HFE

- MRI

Serum ferritin testing is a low-cost, readily available, and minimally invasive method for assessing body iron stores. However, the major problem with using it as an indicator of iron overload is that it can be elevated in a range of other medical conditions unrelated to iron levels including infection, inflammation, fever, liver disease, kidney disease, and cancer. Also, total iron binding capacity may be low, but can also be normal.

The standard of practice in diagnosis of haemochromatosis was recently reviewed by Pietrangelo. Positive HFE analysis confirms the clinical diagnosis of haemochromatosis in asymptomatic individuals with blood tests showing increased iron stores, or for predictive testing of individuals with a family history of haemochromatosis. The alleles evaluated by HFE gene analysis are evident in ~80% of patients with haemochromatosis; a negative report for HFE gene does not rule out haemochromatosis. In a patient with negative HFE gene testing, elevated iron status for no other obvious reason, and family history of liver disease, additional evaluation of liver iron concentration is indicated. In this case, diagnosis of haemochromatosis is based on biochemical analysis and histologic examination of a liver biopsy. Assessment of the hepatic iron index (HII) is considered the "gold standard" for diagnosis of haemochromatosis.

Magnetic resonance imaging (MRI) is emerging as a noninvasive alternative to accurately estimate iron deposition levels in the liver as well as heart, joints, and pituitary gland.

LID is present in stage 1 and 2, before anemia occurs in stage 3. These first two stages can be interpreted as depletion of iron stores and reduction of effective iron transport.

Stage 1 is characterized by loss of bone marrow iron stores while hemoglobin and serum iron levels remain normal. Serum ferritin falls to less than 20 ng/mL. Increased iron absorption, a compensatory change, results in an increased amount transferrin and consequent increased iron-binding capacity.

Stage 2 - Erythropoiesis is impaired. In spite of an increased level of transferrin, serum iron level is decreased along with transferrin saturation. Erythropoiesis impairment begins when the serum iron level falls to less than 50 μg/dL and transferrin saturation is less than 16%.

In stage 3, anemia (reduced hemoglobin levels) is present but red blood cell appearance remains normal.

Changes in the appearance of red blood cells are the hallmark of stage 4; first microcytosis and then hypochromia develop.

Iron deficiency begins to affect tissues in stage 5, manifesting as symptoms and signs.

Blood transfusion is sometimes used to treat iron deficiency with hemodynamic instability. Sometimes transfusions are considered for people who have chronic iron deficiency or who will soon go to surgery, but even if such people have low hemoglobin, they should be given oral treatment or intravenous iron.

The diagnosis of atransferrinemia is done via the following means to ascertain if an individual has the condition:

- Blood test(for anemia)

- TF level

- Physical exam

- Genetic test

There are two forms of this condition that causes an absence of transferrin in the affected individual:

- Acquired atransferrinemia

- Congenital atransferrinemia

Copper deficiency is a very rare disease and is often misdiagnosed several times by physicians before concluding the deficiency of copper through differential diagnosis (copper serum test and bone marrow biopsy are usually conclusive in diagnosing copper deficiency). On average, patients are diagnosed with copper deficiency around 1.1 years after their first symptoms are reported to a physician.

Copper deficiency can be treated with either oral copper supplementation or intravenous copper. If zinc intoxication is present, discontinuation of zinc may be sufficient to restore copper levels back to normal, but this usually is a very slow process. People who suffer from zinc intoxication will usually have to take copper supplements in addition to ceasing zinc consumption. Hematological manifestations are often quickly restored back to normal. The progression of the neurological symptoms will be stopped by appropriate treatment, but often with residual neurological disability.

Diagnosis of this disorder depends on blood tests demonstrating the absence of serum ceruloplasmin, combined with low serum copper concentration, low serum iron concentration, high serum ferritin concentration, or increased hepatic iron concentration. MRI scans can also confirm a diagnosis; abnormal low intensities can indicate iron accumulation in the brain.

Children of affected individuals are obligate carriers for aceruloplasminemia. If the CP mutations has been identified in a related individual, prenatal testing is recommended. Siblings of those affected by the disease are at a 25% of aceruloplasminemia. In asymptomatic siblings, serum concentrations of hemoglobin and hemoglobin A1c should be monitored.

To prevent the progression of symptoms of the disease, annual glucose tolerance tests beginning in early teen years to evaluate the onset of diabetes mellitus. Those at risk should avoid taking iron supplements.

The characteristic hematological (blood) effects of copper deficiency are anemia (which may be microcytic, normocytic or macrocytic) and neutropenia. Thrombocytopenia (low blood platelets) is unusual.

The peripheral blood and bone marrow aspirate findings in copper deficiency can mimic myelodysplastic syndrome. Bone marrow aspirate in both conditions may show dysplasia of blood cell precursors and the presence of ring sideroblasts (erythroblasts containing multiple iron granules around the nucleus). Unlike most cases of myelodysplastic syndrome, the bone marrow aspirate in copper deficiency characteristically shows cytoplasmic vacuoles within red and white cell precursors, and karyotyping in cases of copper deficiency does not reveal cytogenetic features characteristic of myelodysplastic syndrome.

Anemia and neutropenia typically resolve within six weeks of copper replacement.

It is unclear if screening pregnant women for iron-deficiency anemia during pregnancy improves outcomes in the United States. The same holds true for screening children who are "6 to 24 months" old.

While the most common symptom of PCT is the appearance of skin lesions and blistering, their appearance does not single-handedly lead to a conclusive diagnosis. Laboratory testing will commonly reveal high levels of uroporphyrinogen in the urine, clinically referred to as uroporphyrinogenuria. Additionally, testing for common risk factors such as Hepatitis C and hemochromatosis is strongly suggested, as their high prevalence in patients with PCT may require additional treatment. If clinical appearance of PCT is present, but laboratories are negative, one needs to seriously consider the diagnosis of pseudoporphyria.

Anemia is often discovered by routine blood tests, which generally include a complete blood count (CBC). A sufficiently low hemoglobin (Hb) by definition makes the diagnosis of anemia, and a low hematocrit value is also characteristic of anemia. Further studies will be undertaken to determine the anemia's cause. If the anemia is due to iron deficiency, one of the first abnormal values to be noted on a CBC, as the body's iron stores begin to be depleted, will be a high red blood cell distribution width (RDW), reflecting an increased variability in the size of red blood cells (RBCs).

A low mean corpuscular volume (MCV) also appears during the course of body iron depletion. It indicates a high number of abnormally small red blood cells. A low MCV, a low mean corpuscular hemoglobin or mean corpuscular hemoglobin concentration, and the corresponding appearance of RBCs on visual examination of a peripheral blood smear narrows the problem to a microcytic anemia (literally, a "small red blood cell" anemia).

The blood smear of a person with iron-deficiency anemia shows many hypochromic (pale, relatively colorless) and small RBCs, and may also show poikilocytosis (variation in shape) and anisocytosis (variation in size). With more severe iron-deficiency anemia, the peripheral blood smear may show hypochromic, pencil-shaped cells and, occasionally, small numbers of nucleated red blood cells. The platelet count may be slightly above the high limit of normal in iron-deficiency anemia (termed a mild thrombocytosis), but severe cases can present with thrombocytopenia (low platelet count).

Iron-deficiency anemia is confirmed by tests that include serum ferritin, serum iron level, serum transferrin, and total iron binding capacity (TIBC). A low serum ferritin is most commonly found. However, serum ferritin can be elevated by any type of chronic inflammation and thus is not consistently decreased in iron-deficiency anemia. Serum iron levels may be measured, but serum iron concentration is not as reliable as the measurement of both serum iron and serum iron-binding protein levels (TIBC). The ratio of serum iron to TIBC (called iron saturation or transferrin saturation index or percent) is a value with defined parameters that can help to confirm the diagnosis of iron-deficiency anemia; however, other conditions must also be considered, including other types of anemia.

Further testing may be necessary to differentiate iron-deficiency anemia from other disorders, such as thalassemia minor. It is very important not to treat people with thalassemia with an iron supplement, as this can lead to hemochromatosis. A hemoglobin electrophoresis provides useful evidence for distinguishing these two conditions, along with iron studies.

Diagnosis of Fatty-acid metabolism disorder requires extensive lab testing.

Normally, in cases of hypoglycaemia, triglycerides and fatty acids are metabolised to provide glucose/energy. However, in this process, ketones are also produced and ketotic hypoglycaemia is expected. However, in cases where fatty acid metabolism is impaired, a non-ketotic hypoglycaemia may be the result, due to a break in the metabolic pathways for fatty-acid metabolism.

The amount of iron ingested may give a clue to potential toxicity. The therapeutic dose for iron deficiency anemia is 3–6 mg/kg/day. Toxic effects begin to occur at doses above 10–20 mg/kg of elemental iron. Ingestions of more than 50 mg/kg of elemental iron are associated with severe toxicity.

- A 325-mg tablet of ferrous sulfate heptahydrate has 65 mg (20%) of elemental iron

- A 325-mg tablet of ferrous gluconate has 39 mg (12%) of elemental iron

- A 325-mg tablet of ferrous fumarate has 107.25 mg (33%) of elemental iron

- 200 mg ferrous sulfate, dried, has 65 mg (33%) of elemental iron

In terms of blood values, iron levels above 350–500 µg/dL are considered toxic, and levels over 1000 µg/dL indicate severe iron poisoning.

Genes involved in iron metabolism disorders include HFE and TFR2.

Hepcidin is the master regulator of iron metabolism and, therefore, most genetic forms of iron overload can be thought of as relative hepcidin deficiency in one way or another. For instance, a severe form of iron overload, juvenile hemochromatosis, is a result of severe hepcidin deficiency. The majority of cases are caused by mutations in the hemojuvelin gene (HJV or RGMc/repulsive guidance molecule c). The exceptions, people who have mutations in the gene for ferroportin, prove the rule: these people have plenty of hepcidin, but their cells lack the proper response to it. So, in people with ferroportin proteins that transport iron out of cells without responding to hepcidin's signals to stop, they have a deficiency in the action of hepcidin, if not in hepcidin itself.

But the exact mechanisms of most of the various forms of adult hemochromatosis, which make up most of the genetic iron overload disorders, remain unsolved. So while researchers have been able to identify genetic mutations causing several adult variants of hemochromatosis, they now must turn their attention to the normal function of these mutated genes.

These genes represent multiple steps along the pathway of iron regulation, from the body's ability to sense iron, to the body's ability to regulate uptake and storage. Working out the functions of each gene in this pathway will be an important tool for finding new methods of treating genetic disorders, as well as for understanding the basic workings of the pathway.

So though many mysteries of iron metabolism remain, the discovery of hepcidin already allows a much better understanding of the nature of iron regulation, and makes researchers optimistic that many more breakthroughs in this field are soon to come.

Dozens of congenital metabolic diseases are now detectable by newborn screening tests, especially the expanded testing using mass spectrometry. This is an increasingly common way for the diagnosis to be made and sometimes results in earlier treatment and a better outcome. There is a revolutionary Gas chromatography–mass spectrometry-based technology with an integrated analytics system, which has now made it possible to test a newborn for over 100 mm genetic metabolic disorders.

Because of the multiplicity of conditions, many different diagnostic tests are used for screening. An abnormal result is often followed by a subsequent "definitive test" to confirm the suspected diagnosis.

Common screening tests used in the last sixty years:

- Ferric chloride test (turned colors in reaction to various abnormal metabolites in urine)

- Ninhydrin paper chromatography (detected abnormal amino acid patterns)

- Guthrie bacterial inhibition assay (detected a few amino acids in excessive amounts in blood) The dried blood spot can be used for multianalyte testing using Tandem Mass Spectrometry (MS/MS). This given an indication for a disorder. The same has to be further confirmed by enzyme assays, IEX-Ninhydrin, GC/MS or DNA Testing.

- Quantitative measurement of amino acids in plasma and urine

- IEX-Ninhydrin post column derivitization liquid ion-exchange chromatography (detected abnormal amino acid patterns and quantitative analysis)

- Urine organic acid analysis by gas chromatography–mass spectrometry

- Plasma acylcarnitines analysis by mass spectrometry

- Urine purines and pyrimidines analysis by gas chromatography-mass spectrometry

Specific diagnostic tests (or focused screening for a small set of disorders):

- Tissue biopsy or necropsy: liver, muscle, brain, bone marrow

- Skin biopsy and fibroblast cultivation for specific enzyme testing

- Specific DNA testing

A 2015 review reported that even with all these diagnostic tests, there are cases when "biochemical testing, gene sequencing, and enzymatic testing can neither confirm nor rule out an IEM, resulting in the need to rely on the patient's clinical course."

There are several methods available for diagnosing and monitoring hemosiderosis including:

- Serum ferritin

- Liver biopsy

- MRI

Serum ferritin is a low cost, readily available, and minimally invasive method for assessing body iron stores. However, the major problem with using it as an indicator of hemosiderosis is that it can be elevated in a range of other medical conditions unrelated to iron levels including infection, inflammation, fever, liver disease, renal disease and cancer.

While liver biopsies provide a direct measure of liver iron concentration, the small sample size relative to the size of the liver can lead to sampling errors given the heterogeneity of iron concentration within the liver. Furthermore, the invasive nature of liver biopsy and the associated risks of complications (which can range from pain, haemorrhage, gallbladder perforation and other morbidities through to death in approx 1 in 10,000 cases) prevent it being used as a regular monitoring tool.

MRI is emerging as an alternative method for measuring liver iron loading because it is non-invasive, safer and generally cheaper to perform than liver biopsy; does not suffer from problems with sampling variability; and can be used more frequently than performing liver biopsies.

Anemia of chronic disease is usually mild but can be severe. It is usually normocytic, but can be microcytic. The presence of both anemia of chronic disease and dietary iron deficiency in the same patient results in a more severe anemia.