Blood group test results interpretation

Knowing your blood group and subgroups is one way to discover specific information about your body’s genetic makeup and susceptibility to disease. This fact sheet is for educational purposes only. For those suffering from a specific condition it is recommended that you get assistance from a healthcare provider. Some practitioners familiar with the significance of blood groups are listed on the internet in the IfHI practitioner registry.

ABO Blood Group: [Gene location: 9q34]. A, B, AB and O are four major blood group divisions that are used for compatibility in blood transfusions, and also mark many genetic differences between people. Research in the 1950s and 60s found a connection between particular disorders (stomach ulcer, stomach cancer, blood clotting disease) and ABO blood groups. A dietary and supplement protocol has been developed according to scientific understanding of digestive ability, metabolism and disease susceptibility relating to each blood group. For more information see the web site and the book Live Right 4 Your Type (LR4YT). You may wish to alter your diet and exercise programme and/or take specific supplements as a result of knowing your ABO blood group.

Rh (Rhesus): [Gene location: 1p36.2-p34] The main antigen of the Rh system is known as D. Apart from their ABO blood group, people are also classified as Rh positive or Rh negative according to the presence or absence of the D antigen in the blood.

Rh D incompatibility is best known as the main cause of newborn fatal blood reactions. Rh status may also affect Natural Killer Cell (immune system) activity and transport of ammonia in the kidney. Some minor dietary variations for Rh negative are noted in LR4YT. More than 46 other Rh groups have been found, but as they do not have major transfusion complications, little research has been done on them.

A Subgroups: There are over 20 subgroups of blood group A (and also of AB). About 95% of blood group A people are A1, the next most prevalent being A2 and then A3. Greenfields ABO  Blood Group Test will check for A1, A2 and A3 in people who are blood group A or AB.

The dietary recommendations for blood group A in Eat Right 4 Your Type are for the A1 group. A2 blood may differ in susceptibility to certain parasites, some types of leukaemia and fungi, and may influence requirement for fats and proteins. For dietary consequences of group A2 or A2B see the book LR4YT. If your result shows you are A3 it is recommended that you follow the dietary guidelines for A non-secretors outlined in LR4YT.

Disclaimer for Blood Transfusion:Your results are for educational purposes only. The ABO blood grouping method used by greenfields lab servicesis a standard monoclonal antibody test to determine ‘front group only’, i.e. only tested on whole blood, unless specifically requested otherwise. In a clinical setting [e.g. transfusion situation] a reverse group testing [an additional blood grouping on plasma as a control test to confirm the initial results from whole blood] is required. Please note that greenfields lab services cannot be held responsible for the consequences of inaccuracies arising from incorrect labelling of samples at the time of collection, for example where multiple samples are batched before posting: ensure each sample is clearly labelled at the time of collection.

Lewis Blood Group and Secretor Status:[Gene location: 19q13.3] The molecule that defines your blood group is called an antigen. People of each blood group have that specific antigen on their red blood cells: A has the A antigen, B has the B antigen AB has both A and B antigens and O has the H antigen. The term "ABH secretor" refers to secretion of ABO blood group antigens in fluids such as saliva, sweat, tears, semen and breast milk. If you are an “ABH secretor”, you will secrete antigens according to your blood group. For example, group O people will secrete H antigen, group A will secrete A and H antigens, etc. Approximately 80% of people are ABH secretors. There are several differences between ABH secretors and non-secretors, especially relating to function of the immune system. There are altered dietary requirements, which are outlined in LR4YT and The Complete Blood Group Encyclopedia

Lewis blood group is a minor blood group that relates to salivary secretor status. Salivary ABH secretor determination is based on testing for your blood group antibodies in your saliva. Finding your Lewis blood group (Lea and Leb) will tell your ABH secretor status in most cases, irrespective of your blood group. Most ABH secretors have a Lewis group of: Lea- Leb+. Most ABH non-secretors have a Lewis group of: Lea+ Leb-. A small minority (1 to 4% of the population) will be Lewis Double Negative (LDN): Lea- Leb-. For LDN people Lewis blood group cannot be used to determine ABH secretor status. ABH gene testing (FUT2) is available from greenfields to test if you have the secretor gene. LDN people share most of the same metabolic consequences as ABH non-secretors, and in a few instances they have the most severe manifestations. According to Dr. D’Adamo “It may be helpful to think of LDN individuals as a special category of non-secretor”.

Although ABH salivary secretor status is often thought of as an ‘all or none’ situation, this is not always the case. Some people known as ‘partial’ or ‘weak secretors’ have a greatly reduced quantity of active A or B blood group substance in their saliva, predisposing them to similar functional problems as non-secretors. In the same way, Lewis antigens can also give a ‘weak’ result. Where relevant, weak Lewis results will be reported, as will Lea+ Leb+ (a rare temporary situation, brought about by circumstances such as pregnancy).

MN Subgroup: [Gene location: 4q28.2-4q31.1] this is independent of both ABO blood group and Lewis blood group. There are three possible types:

MN: the majority (no dietary changes indicated);

MM: less common, associated with altered cancer risk (several suggested dietary changes in LR4YT); and

NN: least common, primarily affecting fat metabolism. Those of NN subgroup appear to have less ability to digest and assimilate fats. While LR4YT does not offer dietary adjustments for NN blood group, it has been suggested that those with NN group benefit by reducing fats, especially cholesterol-containing foods in their diets.

Variations in the MN subgroup may be associated with differences in longevity, susceptibility to alcoholism, bipolar depression, asthma and essential hypertension.

Duffy blood group: [Gene location: 1q22-1q23] this is independent of both ABO blood group and Lewis blood group. There are four possible types:

fya- fyb- (Duffy negative)

fya+ fyb-

fya- fyb+

fya+ fyb+

There are no dietary changes listed in LR4YT for Duffy blood group, this blood group is used in the SWAMI software by Dr. Peter D'Adamo. There are some possible disease risk associations with Duffy blood group, including inflammation, cancer, susceptibility to some forms of malaria, total IgE levels, susceptibility to HIV infection and disease progression, and others. The Duffy antigen may cause a transfusion reaction in Duffy incompatible individuals.


greenfields clinic & health store
37 Northgate Canterbury,
Kent CT1 1BL

Tel: 01227 454 848



  • Avatar
    Margret van der Elst
    I wanted to know if I'm a secretor or a non secretor.
    That's why I ordered the kit and sent my blood.

    This is only a information !

    When will I get the result ?

    Regards Margret van der Elst
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