Supplementary Table 1. Descriptions and methods of advertisement for recruitment platforms

Platform / Type / Description / Advertising method
Bender / Social networking / Enables communication with men interested in dating men / Pop-up announcements
BlackGayChat / Social networking / Enables communication with gay, bisexual, and transgender black and Latino men / Banner advertisements
Facebook / Social media / Enables communication with friends / Sponsored Facebook page posts
Grindr / Social networking / Enables communication with men interested in men / Broadcast messages
Growlr / Social networking / Enables communication with gay bears / Pop-up announcements
Pinterest / Social bookmarking / Enables sharing of media content / Pin
Reddit / Social bookmarking / Enables sharing of aggregated social news / Subreddit posts

Supplementary Table 2. Participant demographic characteristics by assigned HIV testing group

Assigned HIV testing group / P-value
Home-based oral fluid
rapid HIV self-test / Home-based mail-in blood sample
collection conventional HIV test / Medical facility/Community
organization-based HIV test
Demographic characteristics / n=142 / n=142 / n=141
Median age, years (IQR) / 22 (20-23) / 23 (20-24) / 22 (21-24) / 0.406*
n (%) / n (%) / n (%)
Race/Ethnicity / 1.000†
Black / 42 (29.6) / 42 (29.6) / 41 (29.1)
Hispanic / 50 (35.2) / 50 (35.2) / 50 (35.5)
White / 50 (35.2) / 50 (35.2) / 50 (35.5)
US geographic region / 0.829†
Northeast / 24 (16.9) / 30 (21.1) / 22 (15.6)
Midwest / 36 (25.4) / 27 (19.0) / 33 (23.4)
South / 54 (38.0) / 56 (39.4) / 58 (41.1)
West / 28 (19.7) / 29 (20.4) / 28 (19.9)
Residential community type / 0.444
Large city or surrounding suburb / 73 (51.4) / 61 (43.0) / 66 (46.8)
Medium city or surrounding suburb / 39 (27.5) / 41 (28.9) / 45 (31.9)
Small city / 10 (7.0) / 23 (16.2) / 15 (10.6)
Town / 12 (8.5) / 10 (7.0) / 8 (5.7)
Rural area / 8 (5.6) / 6 (4.2) / 7 (5.0)
Don't know / 0 (0.0) / 1 (0.7) / 0 (0.0)
Primary care provider/clinic status / 0.959
Have a provider/clinic / 92 (64.8) / 97 (68.3) / 94 (66.7)
No provider/clinic / 49 (34.5) / 44 (31.0) / 46 (32.6)
Don't know / 1 (0.7) / 1 (0.7) / 1 (0.7)
Health care insurance status / 0.566
Insured / 109 (76.8) / 102 (71.8) / 113 (80.1)
Not insured / 31 (21.8) / 38 (26.8) / 27 (19.2)
Don't know / 2 (1.4) / 2 (1.4) / 1 (0.7)
Years of formal education / 0.157
Have not received high school diploma or GED / 6 (4.2) / 5 (3.5) / 2 (1.4)
Received high school diploma or GED / 14 (9.9) / 8 (5.6) / 17 (12.1)
Have not received bachelor's degree / 95 (66.9) / 88 (62.0) / 87 (61.7)
Received bachelor's degree or higher / 26 (18.3) / 41 (28.9) / 35 (24.8)
Refuse to answer / 1 (0.7) / 0 (0.0) / 0 (0.0)
Living alone / 0.443
Yes / 33 (23.2) / 44 (31.0) / 37 (26.2)
No / 108 (76.1) / 97 (68.3) / 104 (73.8)
Don't know / 1 (0.7) / 1 (0.7) / 0 (0.0)

*Kruskal-Wallis test with correction for ties P-value

†Pearson's chi-squared test for independence P-value

Note: All P-values are for Fisher's exact test, unless otherwise specified.

IQR = interquartile range

US = United States

GED = General Education Development

Supplementary Table 3. Participant HIV testing history by assigned HIV testing group

Assigned HIV testing group / P-value
Home-based oral fluid
rapid HIV self-test / Home-based mail-in blood sample
collection conventional HIV test / Medical facility/Community
organization-based HIV test
n=142 / n=142 / n=141
HIV testing history / n (%) / n (%) / n (%)
Ever donated blood / 0.974
Yes / 70 (49.3) / 72 (50.7) / 72 (51.1)
No / 71 (50.0) / 69 (48.6) / 69 (48.9)
Don't know / 1 (0.7) / 0 (0.0) / 0 (0.0)
Refuse to answer / 0 (0.0) / 1 (0.7) / 0 (0.0)
Last blood donation / 0.668
Less than one month ago / 0 (0.0) / 3 (2.1) / 2 (1.4)
Between one to six months ago / 12 (8.5) / 11 (7.8) / 7 (5.0)
Between six months to one year ago / 3 (2.1) / 5 (3.5) / 2 (1.4)
Between one year to two years ago / 20 (14.1) / 13 (9.2) / 17 (12.1)
More than two years ago / 35 (24.7) / 40 (28.2) / 44 (31.2)
Not applicable (never donated blood) / 71 (50.0) / 69 (48.6) / 69 (48.9)
Don't know/Refuse to answer / 1 (0.7) / 1 (0.7) / 0 (0.0)
How often tested for HIV / 0.453*
At least three times per year / 32 (22.5) / 36 (25.4) / 33 (23.4)
Twice per year / 33 (23.2) / 39 (27.5) / 41 (29.1)
Once per year / 29 (20.4) / 14 (9.9) / 20 (14.2)
Every two years / 6 (4.2) / 6 (4.2) / 6 (4.3)
Two to five years / 3 (2.1) / 0 (0.0) / 0 (0.0)
More than every five years / 0 (0.0) / 1 (0.7) / 1 (0.7)
Tested only once / 15 (10.6) / 20 (14.1) / 16 (11.4)
Not applicable (never tested for HIV) / 23 (16.2) / 23 (16.2) / 23 (16.3)
Don't know/Refuse to answer / 1 (0.7) / 3 (2.1) / 1 (0.7)
Last HIV test / 0.483*
Less than one month / 30 (21.1) / 18 (12.7) / 26 (18.4)
Between one to six months / 44 (31.0) / 68 (47.9) / 56 (39.7)
Between six months to one year / 24 (16.9) / 15 (10.6) / 17 (12.1)
Between one year to two years / 15 (10.6) / 12 (8.5) / 15 (10.6)
More than two years / 4 (2.8) / 4 (2.8) / 3 (2.1)
Not applicable (never tested for HIV) / 23 (16.2) / 23 (16.2) / 23 (16.3)
Don't know/Refuse to answer / 2 (1.4) / 2 (1.4) / 1 (0.7)
Asking provider for HIV test / 0.475
Not comfortable / 33 (23.2) / 23 (16.2) / 28 (19.9)
Somewhat comfortable / 29 (20.4) / 40 (28.2) / 40 (28.4)
Comfortable / 32 (22.5) / 34 (23.9) / 25 (17.7)
Very comfortable / 44 (31.0) / 43 (30.3) / 47 (33.3)
Don't know / 4 (2.8) / 2 (1.4) / 1 (0.7)
Chance of being infected with HIV / 0.164
Very likely / 2 (1.4) / 1 (0.7) / 0 (0.0)
Likely / 0 (0.0) / 2 (1.4) / 1 (0.7)
Somewhat likely / 18 (12.7) / 23 (16.2) / 12 (8.5)
Not likely / 79 (55.6) / 88 (62.0) / 95 (67.4)
Not possible at all / 39 (27.5) / 23 (16.2) / 29 (20.6)
Don't know / 4 (2.8) / 4 (2.8) / 4 (2.8)
Refuse to answer / 0 (0.0) / 1 (0.7) / 0 (0.0)
History of any HIV test / 0.996
Donated blood, and tested not from blood donation / 56 (39.4) / 60 (42.3) / 59 (41.8)
Tested, but not part of blood donation / 62 (43.7) / 58 (40.9) / 58 (41.1)
Tested, only as part of blood donation / 14 (9.9) / 12 (8.5) / 13 (9.2)
No known HIV test / 9 (6.3) / 11 (7.8) / 11 (7.8)
Don't know / 1 (0.7) / 1 (0.7) / 0 (0.0)
Location and type of previous HIV test / 0.497*
Community organization: Conventional HIV test / 5 (3.5) / 10 (7.0) / 10 (7.1)
Community organization: Rapid HIV test / 40 (28.2) / 36 (25.4) / 36 (25.5)
Medical facility: Conventional HIV test / 40 (28.2) / 48 (33.8) / 39 (27.7)
Medical facility: Rapid HIV test / 17 (12.0) / 13 (9.2) / 12 (8.5)
Home: Conventional HIV test (Home Access Express®) / 3 (2.1) / 2 (1.4) / 3 (2.1)
Home: Rapid HIV test (OraQuick®) / 15 (10.6) / 7 (4.9) / 19 (13.5)
Prison/Jail: Conventional HIV test / 0 (0.0) / 1 (0.7) / 0 (0.0)
Prison/Jail: Rapid HIV test / 0 (0.0) / 0 (0.0) / 1 (0.7)
Never been tested for HIV / 19 (13.4) / 22 (15.5) / 21 (14.9)
Don't know / 3 (2.1) / 3 (2.1) / 0 (0.0)

*Pearson's chi-squared test for independence P-value

Note: All P-values are for Fisher's exact test, unless otherwise specified.

Supplementary Table 4. Participant sexual risk-taking behavior history by assigned HIV testing group

Assigned HIV testing group / P-value
Home-based oral fluid
rapid HIV self-test / Home-based mail-in blood sample
collection conventional HIV test / Medical facility/Community
organization-based HIV test
n=142 / n=142 / n=141
Sexual risk-taking behavior history / n (%) / n (%) / n (%)
Vaginal or anal sex with a woman without condoms / 0.485
Yes / 18 (12.7) / 20 (14.1) / 26 (18.4)
No / 124 (87.3) / 121 (85.2) / 114 (80.9)
Don't know / 0 (0.0) / 1 (0.7) / 1 (0.7)
Last vaginal or anal sex with a woman without condoms / 0.155
Less than a month / 1 (0.7) / 4 (2.8) / 0 (0.0)
Between one to six months / 2 (1.4) / 2 (1.4) / 4 (2.8)
Between six months to one year / 2 (1.4) / 3 (2.1) / 0 (0.0)
Between one to two years / 2 (1.4) / 1 (0.7) / 1 (0.7)
More than two years ago / 10 (7.0) / 10 (7.0) / 21 (14.9)
Not applicable (no vaginal or anal sex without condoms) / 124 (87.3) / 121 (85.2) / 114 (80.9)
Don't know / 1 (0.7) / 1 (0.7) / 1 (0.7)
Main / Casual / Exchange / Main / Casual / Exchange / Main / Casual / Exchange / Main / Casual / Exchange
x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / 0.305† / 0.004† / 0.259†
Number of female vaginal or anal sex partners without condoms / 1.5 (0.7) / 1.8 (1.0) / 1.5 (0.7) / 9.0 (27.4) / 22.8 (62.3) / 100.7 (172.6) / 1.2 (0.6) / 1.1 (0.4) / 1.0 (0.0)
Anal sex with a man without condoms (top) / 0.595*
Yes / 112 (78.9) / 109 (76.8) / 104 (73.8)
No / 30 (21.1) / 33 (23.2) / 37 (26.2)
Last anal sex with a man without condoms (top) / 0.537*
Less than a month ago / 35 (24.7) / 41 (28.9) / 31 (22.0)
Between one to six months / 37 (26.1) / 33 (23.2) / 36 (25.5)
Between six months to one year / 19 (13.4) / 16 (11.3) / 14 (9.9)
Between one to two years / 10 (7.0) / 14 (9.9) / 10 (7.1)
More than two years ago / 11 (7.8) / 4 (2.8) / 13 (9.2)
Not applicable (no anal sex without condoms) / 30 (21.1) / 33 (23.2) / 37 (26.2)
Don't know / 0 (0.0) / 1 (0.7) / 0 (0.0)
Main / Casual / Exchange / Main / Casual / Exchange / Main / Casual / Exchange / Main / Casual / Exchange
x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / 0.705† / 0.059† / 0.050†
Number of male anal sex partners without condoms (top) / 2.8 (2.3) / 9.7 (34.1) / 4.8 (4.2) / 5.2 (13.2) / 12.3 (32.2) / 33.7 (113.6) / 2.8 (4.1) / 6.8 (14.8) / 2.3 (2.3)
Anal sex with a man without condoms (bottom) / 0.901*
Yes / 110 (77.5) / 108 (76.1) / 106 (75.2)
No / 32 (22.5) / 34 (23.9) / 35 (24.8)
Last anal sex with a man without condoms (bottom) / 0.462*
Less than a month ago / 44 (31.0) / 39 (27.5) / 39 (27.7)
Between one to six months / 29 (20.4) / 30 (21.1) / 38 (27.0)
Between six months to one year / 16 (11.3) / 19 (13.4) / 6 (4.3)
Between one to two years / 12 (8.5) / 11 (7.8) / 11 (7.8)
More than two years ago / 9 (6.3) / 8 (5.6) / 12 (8.5)
Not applicable (no anal sex without condoms) / 32 (22.5) / 34 (23.9) / 35 (24.8)
Don't know / 0 (0.0) / 1 (0.7) / 0 (0.0)
Main / Casual / Exchange / Main / Casual / Exchange / Main / Casual / Exchange / Main / Casual / Exchange
x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / x̅ (SD) / 0.968† / 0.140† / 0.102†
Number of male anal sex partners without condoms (bottom) / 2.5 (2.0) / 8.2 (28.4) / 4.3 (5.1) / 17.5 (117.7) / 72.5 (562.0) / 561.8 (2355.5) / 2.4 (1.7) / 9.0 (33.7) / 2.1 (1.4)

*Pearson's chi-squared test for independence P-value

†Kruskal-Wallis test with correction for ties P-value

Note: All P-values are for Fisher's exact test, unless otherwise specified.

x̅ = mean

SD = standard deviation