Replies

Factors Known to Cause
False Positive HIV Antibody Test Results
1.Anti-carbohydrate antibodies 52,19,13
2.Naturally-occurring antibodies 5,19
3.Passive immunization: receipt of gamma globulin or immune (as prophylaxis against infection which contains antibodies) 18, 26, 60, 4,
22, 42, 43, 13
4.Leprosy 2, 25
5.Tuberculosis 25
6.Mycobacterium avium 25
7.Systemic lupus erythematosus 15, 23
8.Renal (kidney) failure 48, 23, 13
9.Hemodialysis/renal failure 56, 16, 41, 10, 49
10.Alpha interferon therapy in hemodialysis patients 54
11.Flu 36
12.Flu vaccination 30, 11, 3, 20, 13, 43
13.Herpes simplex I 27
14.Herpes simplex II 11
15.Upper respiratory tract infection (cold or flu) 11
16.Recent viral infection or exposure to viral vaccines 11
17.Pregnancy in multiparous women 58, 53, 13, 43, 36
18.Malaria 6, 12
19.High levels of circulating immune complexes 6, 33
20.Hypergammaglobulinemia (high levels of antibodies) 40, 33
21.False positives on other tests, including RPR (rapid plasma
reagent) test for syphilis 17, 48, 33, 10, 49
22.Rheumatoid arthritis 36
23.Hepatitis B vaccination 28, 21, 40, 43
24.Tetanus vaccination 40
25.Organ transplantation 1, 36
26.Renal transplantation 35, 9, 48, 13, 56
27.Anti-lymphocyte antibodies 56, 31

28.Anti-collagen antibodies (found in gay men, haemophiliacs, Africans of both sexes and people with leprosy) 31

29.Serum-positive for rheumatoid factor, antinuclear antibody (both found in rheumatoid arthritis and other autoantibodies) 14, 62, 53
30.Autoimmune diseases 44, 29, 1O, 40, 49, 43
31.Systemic lupus erythematosus, scleroderma, connective tissue disease, dermatomyositis Acute viral infections, DNA viral infections 59,
48, 43, 53, 40, 13
32.Malignant neoplasms (cancers) 40
33.Alcoholic hepatitis/alcoholic liver disease 32, 48, 40, 10, 13, 49, 43, 53
34.Primary sclerosing cholangitis 48, 53
35.Hepatitis 54
36."Sticky" blood (in Africans) 38, 34, 40
37.Antibodies with a high affinity for polystyrene (used in the test kits) 62, 40, 3
38.Blood transfusions, multiple blood transfusions 63, 36, 13, 49, 43, 41
39.Multiple myeloma 10, 43, 53
40.HLA antibodies (to Class I and II leukocyte antigens) 7, 46, 63, 48, 10, 13, 49, 43, 53
41.Anti-smooth muscle antibody 48
42.Anti-parietal cell antibody 48
43.Anti-hepatitis A IgM (antibody) 48
44.Anti-Hbc IgM 48
45.Administration of human immunoglobulin preparations pooled before 1985 10

46.Haemophilia 10, 49

47.Haematologic malignant disorders/lymphoma 43, 53, 9, 48, 13
48.Primary biliary cirrhosis 43, 53, 13, 48
49.Stevens-Johnson syndrome 9, 48, 13
50.Q-fever with associated hepatitis 61
51.Heat-treated specimens 51, 57, 24, 49, 48
52.Lipemic serum (blood with high levels of fat or lipids) 49
53.Haemolyzed serum (blood where haemoglobin is separated from red cells) 49
54.Hyperbilirubinemia 10, 13
55.Globulins produced during polyclonal gammopathies (which are seen in AIDS risk groups) 10, 13, 48 cross-reactions 10
57.Normal human ribonucleoproteins 48, 13
58.Other retroviruses 8, 55, 14, 48, 13
59.Anti-mitochondrial antibodies 48, 13
60.Anti-nuclear antibodies 48, 13, 53
61.Anti-microsomal antibodies 34
62.T-cell leukocyte antigen antibodies 48, 13
63.Proteins on the filter paper 13
64.Epstein-Barr virus 37
65.Visceral leishmaniasis 45
66.Receptive anal sex 39, 64

Christine Johnson, a researcher and author, compiled this list of conditions documented in the scientific literature to cause positives on HIV tests, and provides references for each condition.
Christine notes:
"Just because something is on this list doesn't mean that it will definitely, or even probably, cause a false-positive. It depends on what antibodies the individual carries as well as the characteristics of each particular test kit.

For instance, some, but not all people who have had blood transfusions, prior pregnancies or an organ transplant will make HLA antibodies. And some, but not all test kits (both ELISA and Western blot) will be contaminated with HLA antigens to which these antibodies can react. Only if these two conditions coincide might you get a false-positive due to HLA cross-reactivity.

There are conditions that are more likely than others to cause false-positives. And there are some conditions that we aren't aware of yet which may be documented in the future to cause false-positives. Some of the factors on the list have been documented only for ELISA, while some have been documented for both ELISA and Western blot (WB) tests.

People may be eager to argue that if a factor is only known to cause false-positives on ELISA, this problem won't be carried over to the WB. But remember, a WB is positive by virtue of accumulating enough individual positive bands to add up to the total required by whatever criteria is used to interpret it 39. So the more exposure a person has had to foreign antigens, proteins and infectious agents, the more various antibodies he or she will have in their system, and the more likely it is
that there will be several cross-reacting antibodies, enough to make the WB positive.

It is to be noted that all AIDS risk groups (and Africans as well), but not the general US or Western European population, have this problem in common: they have been exposed to a plethora of foreign antigens and proteins. This is why people in the AIDS "risk groups" tend to have positive WBs (i.e., to be considered "HIV-infected") and people in the population don't. However, even people in low-risk populations have false-positive Western blots for poorly understood reasons 47.

Since false-positives to every single HIV protein have been documented 36, how do we know if the positive WB bands represent the various proteins to HIV, or a collection of false-positive bands reacting to several different non-HIV antibodies?"