Package Inserts




RAPID DIAGNOSTIC TESTS — HIGH YIELD REVIEWER

1. RPR CARBON ANTIGEN (Fortress Diagnostics) Test for: Syphilis

  • Detects reagin antibodies in serum or plasma using carbon particles coated with cardiolipin antigen

  • Specimen: serum or plasma, stable 48h at 2-8°C

  • Rotate at 100 RPM for 8 minutes

  • Results read within 1 minute of removing from rotator

  • Readings: SR (Strong Reactive), R (Reactive), WR (Weakly Reactive), TR (Trace Reactive), NR (Non-Reactive)

  • Reactive sera can be titrated via serial 2-fold dilutions in 9g/L saline; titer = highest dilution showing positive result

2. RHELAX-RF (Tulip Diagnostics) Test for: Rheumatoid Factors (IgM class)

  • Principle: latex agglutination; latex coated with Fc fraction of IgG

  • Detects ≥10 IU/ml RF

  • Specimen: serum ONLY (plasma = risk of false positives)

  • Read at exactly 2 minutes (not beyond)

  • RF formula: RF (IU/ml) = Sensitivity (10 IU/ml) × Highest dilution showing agglutination

  • RF present in ~80% of RA cases; also found in syphilis, SLE, hepatitis, hypergammaglobulinemia

  • Prozone-free between 10–2300 IU/ml

  • Sensitivity 100%, Specificity 100% (per insert)

3. Abbott Determine HBsAg Test for: Hepatitis B Surface Antigen

  • Immunochromatographic test; selenium colloid-antibody conjugate

  • Specimens: serum, plasma, whole blood (venipuncture or fingerstick)

  • Whole blood by fingerstick: apply 50µL + 1 drop Chase Buffer → wait 15–24 hours

  • For whole blood by venipuncture: apply 50µL + 1 drop Chase Buffer → wait 15–24 hours

  • Serum/plasma: apply 50µL → wait 15–24 hours (no Chase Buffer needed)

  • EDTA tubes required for whole blood by venipuncture

  • Positive = red bars in BOTH Control and Patient windows

  • Negative = red bar in Control window ONLY

  • Invalid = no red bar in Control window

  • Sensitivity (serum): 94.64%; (whole blood): 98.36%

  • Specificity: 99.85–100%

4. RightSign HBsAg Rapid Test Cassette Test for: Hepatitis B Surface Antigen (serum/plasma)

  • Apply 3 drops (~120µL) of serum or plasma

  • Read at 15–30 minutes; do NOT read after 30 minutes

  • Sensitivity: 99.8%; Specificity: 99.6%; Accuracy: 99.7%

  • Can detect as low as 1 PEI ng/ml

  • No cross-reactivity with HAMA, RF, HAV, Syphilis, HIV, H. pylori, MONO, CMV, Rubella, HCV, HEV, TOXO

5. Abbott Bioline Dengue Duo (SD BIOLINE) Test for: Dengue NS1 Ag + IgG/IgM simultaneously

  • Left side = NS1 Ag assay; Right side = IgG/IgM assay

  • Specimens: serum, plasma, whole blood (venipuncture only — NO capillary blood)

  • NS1 Ag: dispense 3 drops (~100µL) into well "S"

  • IgG/IgM: draw 10µL via capillary pipette + 4 drops assay diluent (within 20 seconds)

  • Read at 15–20 minutes; do NOT read after 20 minutes

  • Store 1–30°C; discard if humidity indicator is GREEN; use only if YELLOW

  • NS1 Ag detectable: day 1–9 after fever onset

  • IgM detectable: day 5–10 (primary); day 4–5 (secondary)

  • IgG: appears day 14 in primary (persists for life); rises day 1–2 in secondary

Result interpretation (IgG/IgM):

  • C only = Negative (retest in 3–5 days if dengue suspected)

  • C + M = IgM positive → Primary dengue

  • C + G = IgG positive → Secondary/past dengue

  • C + M + G = Both positive → Late primary or early secondary dengue

  • No C = Invalid → Repeat with new device

Performance:

  • NS1 Ag: Sensitivity 92.4%, Specificity 98.4%

  • IgG/IgM: Sensitivity 94.2%, Specificity 96.4%

  • No cross-reactivity with Japanese Encephalitis, Yellow Fever, Malaria P. falciparum, P. vivax

  • Cross-reactivity with other Flaviviruses (West Nile, Zika, etc.) is possible

6. RightSign hCG Pregnancy Rapid Test Test for: Human Chorionic Gonadotropin (hCG)

  • Detects hCG in plasma, serum, and urine at sensitivity of 25 mIU/mL

  • Apply 3 drops of specimen; read at 3 minutes for urine, 5 minutes for serum/plasma

  • Do NOT read after 10 minutes

  • Positive = lines in both C and T regions

  • Negative = line in C region only (one line)

  • Invalid = no line in C region

  • Sensitivity >99.9%; Specificity >99.9%; Accuracy >99.9%

  • No cross-reactivity with LH (300 mIU/mL), FSH (1000 mIU/mL), TSH (1000 µIU/mL)

7. Beacon ASO Latex Test for: Anti-Streptolysin O (ASO)

  • Slide agglutination using latex particles coated with Streptolysin O (SLO), pH 8.2

  • Rotate at 80–100 RPM for 2 minutes (false positives if read later)

  • Place 50µL sample + 1 drop (50µL) ASO latex reagent per circle

  • Agglutination = ASO ≥200 IU/mL

  • Formula: 200 × ASO Titer = IU/mL

  • Reference values: ≤200 IU/mL (adults); ≤100 IU/mL (children <5 years)

  • Diagnostic sensitivity: 98%; Specificity: 97%

  • False positives: RA, scarlet fever, tonsillitis, streptococcal infections, healthy carriers

  • False negatives: early infections, children 6 months–2 years

  • No prozone effect up to 1500 IU/mL

  • Calibrated against ASO International Standard NIBSC 97/662

KEY COMPARATIVE MNEMONICS

Test

Specimen

Read Time

Rotate?

RPR

Serum/Plasma

Within 1 min of stopping rotation

100 RPM, 8 min

RHELAX-RF

Serum ONLY

Exactly 2 min

Yes

HBsAg Determine

Serum/Plasma/WB

15–24 hours

No

HBsAg RightSign

Serum/Plasma

15–30 min

No

Dengue Duo

Serum/Plasma/WB

15–20 min

No

hCG RightSign

Serum/Plasma/Urine

3–5 min / max 10 min

No

ASO Latex

Serum

Exactly 2 min

80–100 RPM, 2 min

COMMON TRAPS TO REMEMBER

  • RHELAX-RF: use serum only; plasma → false positives

  • Dengue IgG/IgM: capillary blood NOT allowed

  • Dengue Duo: discard device if humidity indicator is GREEN

  • ASO and RPR: reading beyond time limit → false positives

  • HBsAg Determine: patient bar lighter than control bar is still POSITIVE

  • RF can be positive in syphilis — don't confuse with RA exclusively

  • Dengue NS1 Ag inhibited by anti-NS1 antibodies in some patients → false negative possible