1 STEP 1: Place one drop of reagent anti-Rho(D) on a labeled slide.
2 STEP 2: Place one drop of albumin or other control medium on
another labeled slide.
3 STEP 3: To each slide add two drops of well mixed 40 to 50 percent
suspension of cells in plasma or serum.
4 STEP 4: Thoroughly mix the cell suspension and reagent, using
a clean stick for each slide, and spread the mixture evenly over most of the slide.
5 STEP 5: Place both slides on the viewing surface
simultaneously, and tilt gently and continuously to observe for agglutination.
6 STEP 6: After no longer than 2 minutes, interpret and record
the results of the reactions on both sides.
Do not allow cell mixture to come in contact with hands.
(b) Interpretation. A positive test has agglutination with anti-Rho(D)
and a smooth suspension of cells in the control. Drying around the edges should not be
confused with agglutination. If there is agglutination or irregularity in the control, a
saline test must be performed (see below).
(c) Du testing cannot be done on a slide. To confirm Rh-negative
results, a tube test should supplement the slide findings.
(d) False positives.
1 If albumin control is positive, disregard results and repeat test
with saline-active reagents.
2 Small fibrin clots may give the appearance of agglutination.
3 Blood incompletely anti-coagulated may clot on the heated
1 Too weak a cell suspension may agglutinate poorly. Whole
blood from a severely anemic patient may not be a sufficiently concentrated cell
2 Cells in a saline suspension react poorly or not at all.