Immunohematology 4.9 - 4.11
Which of the following bands would constitute a positive Western Blot for HIV? A. p24, gp41, p17 B. p55, gp120, p51 C. gp160, p31, p56 D. p24, p30, p55
A. p24, gp41, p17 According to current FDA and CDC criteria, a sample is defined as anti-HIV positive if at least two of the following bands are present on a Western Blot: p24, gp41, and/or GP120/160.
An EIA screening test for HTLV I/II was performed on a whole-blood donor. "e results of the EIA were repeatedly reactive but the confirmatory test was negative. On the next donation, the screening test was negative by two different EIA tests. "e donor should be: A. Accepted B. Deferred C. Told that only plasma can be made from his donation D. Told to come back in 6 months
A. Accepted If screening results are repeatedly reactive and the confirmatory test is negative for anti-HTLV and upon the next donation the EIA is negative by two different methods, the donor may be accepted.
Which blood type may be transfused to an AB-positive baby who has HDN caused by anti-D? A. AB negative, CMV negative, Hgb S negative; irradiated or O negative, CMV negative, Hgb S negative B. AB positive, CMV negative; irradiated or O positive, CMV negative C. AB negative only D. O negative only
A. AB negative, CMV negative, Hgb S negative; irradiated or O negative, CMV negative, Hgb S negative Either AB-negative or O-negative RBCs may be given to an AB-positive baby because both types are ABO compatible and lack the D antigen.
What testing is done for exchange transfusion when the mother's serum contains an alloantibody? A. Crossmatch and antibody screen B. ABO, Rh, antibody screen, and crossmatch C. ABO, Rh, antibody screen D. ABO and Rh only
B. ABO, Rh, antibody screen, and crossmatch ABO (forward) and Rh are required. An antibody screen using either the neonatal serum or maternal serum is required. A crossmatch is necessary as long as maternal antibody persists in the infant's blood.
All of the following are required tests on donor blood, except: A. HBsAg B. Anti-CMV C. HIV-1 D. Anti-HTLV I/II
B. Anti-CMV Testing of donor blood for antibodies to CMV is not required. However, testing may be done on units intended for transfusion to low birth weight infants born to seronegative mothers or units used for intrauterine transfusion; units intended for immunocompromised patients who are seronegative; prospective transplant recipients who are seronegative; or transplant recipients who have received a seronegative organ. Leukoreduced RBCs carry a reduced risk of transmitting CMV and are recommended for such patients when CMV testing has not been performed on donor units. The prevalence of anti-CMV in the population ranges from 40%-90%.
All of the following are routinely performed on a cord blood sample except: A. Forward ABO typing B. Antibody screen C. Rh typing D. DAT
B. Antibody screen An antibody screen is not performed routinely on a cord blood sample because a baby does not make antibodies until about 6 months of age. Any antibodies detected in a cord blood sample come from the mother
Four units of blood are ordered for a patient. Blood bank records are checked and indicate that 5 years ago this patient had an anti-Jk^b. What is the next course of action? A. Antigen type units for the Jk^b antigen and only crossmatch units positive for Jk^b B. Antigen type units for the Jk^b antigen and only crossmatch units negative for Jk^b C. Randomly pull 4 units of blood that are ABO compatible and crossmatch D. Perform an immediate spin crossmatch on 4 Jkb-negative units
B. Antigen type units for the Jk^b antigen and only crossmatch units negative for Jk^b A patient with a history of a significant antibody like anti-Jk^b must receive blood that has been completely crossmatched and negative for the corresponding antigen; otherwise, an anamnestic reaction may occur with subsequent lysis of donor cells.
What marker is the first to appear in hepatitis B infection? A. Anti-HBc (IgM) B. HbsAg C. Anti-HBs D. Anti-HBc (IgG)
B. HbsAg The first viral marker of hepatitis B to appear in the serum once exposed is the HBSAg, which appears in as few as 5 days (5-28 days postexposure).
A fetal screen yielded negative results on a mother who is O negative and infant who is O positive. What course of action should be taken? A. Perform a Kleihauer-Betke test B. Issue one full dose of RhIg C. Perform a DAT on the infant D. Perform an antibody screen on the mother
B. Issue one full dose of RhIg If the fetal screen or rosette test is negative, indicating the fetal maternal blood is negligible in a possible RhIg candidate, standard practice is to issue one dose of RhIg.
What can be done if HDN is caused by maternal anti-K? A. Give Kell immune globulin B. Monitor the mother's antibody level C. Prevent formation of K-positive cells in the fetus D. Not a problem; anti-K is not known to cause HDN
B. Monitor the mother's antibody level Anti-D is the only antibody for which prevention of HDN is possible. If a pregnant woman develops anti-K, she will be monitored to determine if the antibody level and signs of fetal distress necessitate clinical intervention.
Which of the following patients would be a candidate for RhIg? A. B-positive mother; B-negative baby; first pregnancy; no anti-D in mother B. O-negative mother; A-positive baby; second pregnancy; no anti-D in mother C. A-negative mother; O-negative baby; fourth pregnancy; anti-D in mother D. AB-negative mother; B-positive baby; second pregnancy; anti-D in mother
B. O-negative mother; A-positive baby; second pregnancy; no anti-D in mother An O-negative mother who gives birth to an A-positive baby and has no anti-D formed from a previous pregnancy would be a candidate for RhIg. A mother who already has active anti-D or a mother who gives birth to an Rh-negative baby is not a candidate for RhIg. Anti-D formation via active immunization typically has a titer >4, compared with passive administration of anti-D, which has a titer <4.
Kernicterus is caused by the effects of: A. Anemia B. Unconjugated bilirubin C. Antibody specificity D. Antibody titer
B. Unconjugated bilirubin Kernicterus occurs because of high levels of unconjugated bilirubin. High levels of this pigment cross into the central nervous system, causing brain damage to the infant.
What marker indicates immunity to hepatitis B infection? A. Anti-HBc (IgM) B. HBsAg C. Anti-HBs D. Anti-HBc (IgG)
C. Anti-HBs Anti-HBs is indicative of immunity or vaccination to hepatitis B. Anti-HBc (IgM) occurs in the early stage of infection; anti-HBc (IgG) follows and may persist for years following infection. HBsAg is a marker of HBV infection, not immunity.
Currently, nucleic acid amplification testing (NAT) testing is performed to detect which viruses? A. HIV and HTLV-1 B. HTLV I/II C. HIV, HCV, and WNV D. HIV, HBV, and WNV
C. HIV, HCV, and WNV According to AABB standards, NAT testing is required for viruses HIV-1, HCV, and WNV.
An O-negative mother with no record of any previous pregnancies gives birth to her first child, a B-positive baby. "e baby's DAT is weakly positive and the negative control is negative. "e antibody screen is also negative. "e baby appears healthy but develops mild jaundice after 2 days, which is treated with phototherapy. "e baby goes home after 4 days in the hospital without complications. What is the most likely explanation for the weakly positive DAT? A. Technical error B. A low titer anti-D C. Immune anti-B from the mother D. A maternal antibody against a low-incidence
C. Immune anti-B from the mother In this case, the maternal anti-A,B is probably coating the infant's B cells, causing a positive DAT and jaundice. Anti-A,B from an O person is a single entity that cannot be separated. It is IgG and can cross the placenta. This antibody may attach to A, B, or AB red cells.
A 56-year-old patient diagnosed with colon cancer demonstrates a positive antibody screen in all three screen cells at the antiglobulin phase. A panel study is done and shows 10 cells positive as well as the autocontrol at the antiglobulin phase. "e reactions varied from 1+ to 3+. "is patient had a history of receiving 2 units of blood approximately 1 month ago. What should be done next? A. Perform a DAT on the patient cells B. Perform an autoadsorption C. Perform an alloadsorption D. Issue O-negative cells
C. Perform an alloadsorption In this situation, an allogeneic adsorption must be performed to adsorb out the autoantibody and leave potential alloantibodies in the patient's serum that will need to be identified before transfusion of blood to the patient. An autoadsorption cannot be performed due to the fact that any alloantibodies would be absorbed by circulating donor cells from a month prior.
What protocol is followed when screening whole blood donors for HIV-1 RNA? A. Pools of 10 are tested; if the pool is nonreactive, donors are accepted B. Pools of 20 are tested; if the pool is reactive, samples are tested individually C. Pools of up to 16 donors are tested; if pool is reactive, individual samples are screened D. All donors are screened individually; if samples are reactive, blood is discarded
C. Pools of up to 16 donors are tested; if pool is reactive, individual samples are screened Pools of up to 16 donors are tested by nucleic acid amplification technology. If the pool is reactive, samples from each individual donor are tested.
An Rh phenotyping shows the following results: Anti-D Anti-C Anti-E Anti-c Anti-e 4+ 2+ 0 0 3+ What is the most likely Rh genotype? A. R^1r´ B. R^0r C. R^1R^1 D. R^1r
C. R^1R^1 The most likely genotype is R1R1. The possibilities are DCe/DCe or DCe/dCe, which translates to R^1R^1 or R^1r´. The former is more common.
What is the best course of action given the following test result? (Assume the patient has not been transfused recently.) Anti-A Anti-B A1 cells B cells Mixed field 0 1+ 4+ A. Nothing, typing is normal B. Type patient cells with anti-A1 lectin and type serum with A2 cells C. Retype patient cells; type with anti-H and anti-A,B; use screen cells or A2 cells on patient serum; run patient autocontrol D. Wash patient cells four times with saline, then repeat the forward type
C. Retype patient cells; type with anti-H and anti-A,B; use screen cells or A2 cells on patient serum; run patient autocontrol The mixed-field reaction with anti-A suggests a subgroup of A, most likely A3. The reverse grouping shows weak agglutination with A1 cells, indicating anti-A1. A positive reaction with anti-A,B would help to differentiate an A subgroup from group O. If A2 cells are not agglutinated by patient serum, the result would indicate the presence of anti-A1. If the patient's serum agglutinates A2 cells, then an alloantibody or autoantibody should be considered.
The following results were obtained on a 51-year-old male with hepatitis C: Anti-A Anti-B Anti-D A1 cells B cells 4+ 4+ 3+ 0 0 What should be done next? A. Retype the patient's sample to confirm group AB positive B. Repeat the Rh typing C. Run a saline control in forward grouping D. Report the patient as group AB, Rh positive
C. Run a saline control in forward grouping In the case of an AB-positive person, a saline control must be run in forward grouping to obtain a negative reaction; this will ensure agglutination is specific in the other reactions.
An anti-M reacts strongly through all phases of testing. Which of the following techniques would not contribute to removing this reactivity so that more clinically significant antibodies may be revealed? A. Acidifying the serum B. Prewarmed technique C. Adsorption with homozygous cells D. Testing with enzyme-treated red cells
A. Acidifying the serum Lowering the pH will actually enhance reactivity of anti-M. Prewarming (anti-M is a cold-reacting antibody), cold adsorption with homozygous M cells, and testing the serum with enzyme-treated red cells (destroys M antigens) are all techniques to remove reactivity of anti-M.
John comes in to donate a unit of whole blood at the collection center of the community blood supplier. "e EIA screen is reactive for anti-HIV-1/2. "e test is repeated in duplicate and is nonreactive. John is: A. Cleared for donation B. Deferred for 6 months C. Status is dependent on confirmatory test D. Deferred for 12 months
A. Cleared for donation If the initial EIA screen for anti-HIV is reactive, and the test is repeated in duplicate and found to be nonreactive, the blood components may be used.
Red cells from a recently transfused patient were DAT positive when tested with anti-IgG. Screen cells and a panel performed on a patient's serum showed very weak reactions with inconclusive results. What procedure could help to identify the antibody? A. Elution followed by a panel on the eluate B. Adsorption followed by a panel on the adsorbed serum C. Enzyme panel D. Antigen typing the patient's red cells
A. Elution followed by a panel on the eluate If the red cells show a positive DAT, then IgG antibody has coated incompatible, antigen-positive red cells. If screening cells and panel cells show missing or weak reactions, most of the antibody is on the red cells and would need to be eluted before it can be detected. An elution procedure followed by a panel performed on the eluate would help to identify the antibody.
A patient's serum contains a mixture of antibodies. One of the antibodies is identified as anti-D. Anti-Jk^a or anti-Fy^a and possibly another antibody are present. What technique(s) may be helpful to identify the other antibody(s)? A. Enzyme panel; select cell panel B. Thio reagents C. Lowering the pH and increasing the incubation time D. Using albumin as an enhancement media in combination with selective adsorption
A. Enzyme panel; select cell panel An enzyme panel would help to distinguish between anti-Jk^a (reaction enhanced) and anti-Fy^a (destroyed). Anti-D, however, would also be enhanced and may mask reactions that may distinguish another antibody. A select panel of cells negative for D may help to reveal an additional antibody or antibodies
Is there a discrepancy between the following blood typing and secretor study results? Blood typing results: Anti-A Anti-B A1 cells B cells 4+ 0 0 4+ Secretor results: Anti-A + saliva + A1 cells = 0 Anti-B + saliva + B cells = 4+ Anti-H + saliva + O cells = 0 A. No problem, the sample is from a group A secretor B. Blood types as A and saliva types as B C. Blood types as A, but the secretor study is inconclusive D. No problem, the sample is from a group A nonsecretor
A. No problem, the sample is from a group A secretor The blood typing result demonstrates A antigen on the red cells and anti-B in the serum. The secretor result reveals the A antigen in the saliva. The A antigen neutralized the anti-A, preventing agglutination when A1 cells were added. Each blood type (except a Bombay) contains some H antigen; therefore, the H antigen in the saliva would be bound by anti-H reagent. No agglutination would occur when the O cells are added.
SITUATION: The Ortho Provue reports a type on a woman who is 6 weeks pregnant with vaginal bleeding as O negative. The woman tells the emergency department physician she is O positive and presents a blood donor card. The medical laboratory scientist performs a test for weak D and observes a 1+ reaction in AHG phase. A Kleihauer-Betke test is negative. Is this woman a candidate for RhIg? A. No, she is Rh positive B. Yes, she is a genetic weak D C. No, there is no evidence of a fetal bleed D. Yes, based upon the Provue results
A. No, she is Rh positive The negative Kleihauer-Betke test confirms that the positive reaction of the woman's RBCs with anti-D at IAT is not the result of a fetal-maternal bleed. The woman is weak D positive, and, therefore, is not a candidate for RhIg. Typically, a test for weak D is not done as part of the obstetric workup. In such cases, if the rosette test is positive, the mother is given RhIg.
Cord cells are washed six times with saline and the DAT and negative control are still positive. What should be done next? A. Obtain a heelstick sample B. Record the DAT as positive C. Obtain another cord sample D. Perform an elution on the cord cells
A. Obtain a heelstick sample If the cord cells contain excessive Wharton's jelly, then further washing or obtaining another cord sample will not solve the problem. A heelstick sample will not contain Wharton's jelly and should give a valid DAT result.
What should be done when a woman who is 24 weeks pregnant has a positive antibody screen? A. Perform an antibody identification panel; titer if necessary B. No need to do anything until 30 weeks gestation C. Administer Rh immune globulin (RhIg) D. Adsorb the antibody onto antigen-positive cells
A. Perform an antibody identification panel; titer if necessary The identification of the antibody is very important at this stage of the pregnancy. If the antibody is determined to be clinically significant, then a titer may determine the strength of the antibody and the need for clinical intervention.
A patient types as O positive. All three screen and red cells from two O-positive donor units show agglutination after incubation at 37°C, and increase in reactivity at the IAT phase of testing. What action should be taken next? A. Perform an autocontrol and direct antiglobulin test on the patient B. Perform an enzyme panel C. Perform an elution D. Choose another 2 units and repeat the crossmatch
A. Perform an autocontrol and direct antiglobulin test on the patient All screening cells and all units are positive at both 37°C and the IAT phase. This indicates the possibility of a high-frequency alloantibody or a warm autoantibody. An autocontrol would help to make this distinction. A positive autocontrol indicates an autoantibody is present; a negative autocontrol and positive screen cells indicates an alloantibody. A DAT would be performed to determine if an antibody has coated the patient's red cells, and is directed against screening cells and donor cells.
A unit tests positive for syphilis using the rapid plasma reagin test (RPR). "e microhemagglutinin assay-Treponema pallidum (MHA-TP) on the same unit is negative. What is the disposition of the unit? A. The unit may be used to prepare components B. The donor must be contacted and questioned further; if the RPR result is most likely a false positive, then the unit may be used C. The unit must be discarded D. Cellular components may be prepared but must be irradiated before issue
A. The unit may be used to prepare components This is a case of a false-positive screening test (RPR). The confirmatory test for treponemal antibodies was negative. The donor unit is acceptable and may be used to prepare blood components.
Should an A-negative woman who has just had a miscarriage receive RhIg? A. Yes, but only if she does not have evidence of active Anti-D B. No, the type of the baby is unknown C. Yes, but only a minidose regardless of trimester D. No, RhIg is given for term pregnancies only
A. Yes, but only if she does not have evidence of active Anti-D When the fetus is Rh positive or the Rh status of the fetus is unknown, termination of a pregnancy from any cause presents a situation in which an Rh-negative patient should receive RhIg. A minidose is used if the pregnancy is terminated in the first trimester.
A 59-year-old male came through the emergency department of a community hospital complaining of dizziness and fatigue. History included no transfusions and a positive rheumatoid factor 1 year ago. His CBC confirmed anemia. A sample was sent to the blood bank for a type and crossmatch. Upon receipt of the sample in the blood bank, the MLS noticed the EDTA sample appeared very viscous. Fearing the sample would clog the ProVue, testing was performed using the tube method. Initial results revealed the following: Anti-A Anti-B Anti-D Rh Control A1 cells B cells 0 0 4+ 2+ 4+ 4+ "e patient's red cells were washed eight times with saline, and testing was repeated giving the following results: Anti-A Anti-B Anti-D Rh Control A1 cells B cells 0 0 4+ 0 4+ 4+ "e antibody screen was negative at IS, 37°C, and AHG phases; check cells were positive. Crossmatch testing using two O-positive donor units revealed a 1+ at immediate spin, and negative results at 37°C and AHG phases. "e check cells were positive. In light of the crossmatch resu
B. Perform a saline replacement for the crossmatch The history of the patient correlates with abnormal plasma proteins causing a positive result with the Rh control. Perform a saline replacement technique to rectify the incompatible crossmatches at immediate spin.
Anti-E is detected in the serum of a woman in the first trimester of pregnancy. "e first titer for anti-E is 32. Two weeks later, the antibody titer is 64 and then 128 after another 2 weeks. Clinically, there are beginning signs of fetal distress. What may be done? A. Induce labor for early delivery B. Perform plasmapheresis to remove anti-E from the mother C. Administer RhIg to the mother D. Perform an intrauterine transfusion using E-negative cells
B. Perform plasmapheresis to remove anti-E from the mother Plasmapheresis removes excess anti-E from the mother and provides a temporary solution to the problem until the fetus is mature enough to be delivered. The procedure may need to be performed several times, depending upon how quickly and how high the levels of anti-E rise. Administration of RhIg would not contribute to solving this problem caused by anti-E. Intrauterine transfusion would not be performed before week 20, and would be considered only if there is evidence of severe hemolytic disease.
The following results were obtained on a 41-year-old female: Anti-A Anti-B A1 cells B cells O cells 4+ 0 3+ 4+ 3+ Due to the discrepant reverse grouping, a panel was performed on patient serum revealing the presence of anti-M. How can the reverse grouping be resolved? A. Repeat the reverse grouping with a 10-minute incubation at room temperature B. Repeat the reverse grouping using A1 cells that are negative for M antigen C. Repeat the reverse grouping using A1 cells that are positive for M antigen D. No further work is necessary
B. Repeat the reverse grouping using A1 cells that are negative for M antigen The scenario showed an antibody in the patient serum directed toward the M antigen, and the M antigen happened to be on the A1 cells in reverse grouping. To solve this problem, find A1 cells negative for the M antigen or enzyme treat the A1 cells to resolve the ABO discrepancy.
"e Ortho Provue does not detect weak forms of the D antigen. Why would running type and screens on the Provue prevent a patient with a weak D phenotype from forming anti-D? A. Weak D persons cannot form anti-D B. The Provue would result the sample as Rh negative; the patient would receive Rh-negative blood C. The Provue would result the sample as Rh positive; the patient would receive Rh-positive blood D. A and C
B. The Provue would result the sample as Rh negative; the patient would receive Rh-negative blood The Ortho Provue would result the patient with a weak D phenotype as Rh negative, and if blood were needed, the patient would receive Rh-negative blood.
SITUATION: John Smith donated a unit of whole blood in May. Red blood cells made from the whole blood were transfused to a recipient of a community hospital in June with no apparent complications. "e blood supplier notified the medical director of the hospital that the donor reported high-risk behavior with another male in April, although viral tests remain negative and the donor is healthy. What course of action should be taken? A. No action should be taken B. The recipient's physician should be notified C. The recipient's physician and the recipient should be notified D. The recipient should be notified
B. The recipient's physician should be notified The recipient's physician should be notified by the medical director to ascertain the current health status of the recipient, if known, and determine what treatment, if any, the recipient should receive.
Why do Rh-negative women tend to have a positive antibody screen compared to Rh-positive women of childbearing age? A. They have formed active anti-D B. They have received RhIg C. They have formed anti-K D. They have a higher rate of transfusion
B. They have received RhIg The most common reason an Rh-negative woman has a positive antibody screen is because of previously receiving RhIg or passive anti-D.
A cord blood workup was ordered on Baby Boy Jones. "e mother is O negative. Results on the baby are as follows: Anti-A Anti-B Anti-A, B Anti-D DAT (poly) 4+ 0 4+ 0 2+ "e test for weak D was positive at AHG. Is the mother an RhIg candidate? A. No, the baby is Rh positive B. Yes, the baby's Rh type cannot be determined due to the positive DAT C. No, the baby is Rh negative D. Yes, the mother is Rh negative
B. Yes, the baby's Rh type cannot be determined due to the positive DAT The baby forward types as an A and the mother is O negative. It is possible that anti-A,B from the mother is attaching to the baby's red cells, causing a positive DAT. In the presence of a positive DAT, a weak test for D is not valid. Therefore, the baby's Rh type is unknown and the mother would be a candidate for RhIg.
An obstetric patient, 34 weeks pregnant, shows a positive antibody screen at the indirect antiglobulin phase of testing. She is group B, Rh negative. "is is her first pregnancy. She has no prior history of transfusion. What is the most likely explanation for the positive antibody screen? A. She has developed an antibody to fetal red cells B. She probably does not have antibodies because this is her first pregnancy, and she has not been transfused; check for technical error C. She received an antenatal dose of RhIg D. Impossible to determine without further testing
C. She received an antenatal dose of RhIg Because the patient has never been transfused or pregnant, she probably has not formed any atypical antibodies. Because she is Rh negative she would have received a dose of RhIg at 28 weeks (antenatal dose) if her prenatal antibody screen had been negative. Although technical error cannot be ruled out, it is far less likely than RhIg administration.
The reactivity of an unknown antibody could be anti-Jka, but the antibody identification panel does not fit this pattern conclusively. Which of the following would not be effective in determining if the specificity is anti-Jka? A. Testing with enzyme-treated cells B. Select panel of homozygous cells C. Testing with AET-treated cells D. Increased incubation time
C. Testing with AET-treated cells AET denatures Kell antigens and has no effect on Kidd antibodies. Because the detection of Kidd antibodies is subject to dosage effect, selection of cells homozygous for the Jka antigen (and longer incubation) would help to detect the presence of the corresponding antibody. Enzyme-treated red cells would also react more strongly in the presence of Kidd antibodies.
All of the following are interventions for fetal distress caused by maternal antibodies attacking fetal cells except: A. Intrauterine transfusion B. Plasmapheresis on the mother C. Transfusion of antigen-positive cells to the mother D. Early induction of labor
C. Transfusion of antigen-positive cells to the mother Transfusion of antigen-positive cells to the mother who already has an antibody might cause a transfusion reaction and/or evoke an even stronger antibody response, possibly causing more harm to the fetus.
A 33-year-old maternity patient is drawn for a type and screen at 36 weeks' gestation. "e following results are found on the Ortho Provue: Anti-A Anti-B Anti-A, B Anti-D A1 cells B cells 3+ 0 4+ 4+ 2+ 4+ SCI SCII SCIII A1 lectin 0 0 0 3+ "e reference lab identified anti-P1 in the patient plasma using enzyme techniques. How could the ABO discrepancy be solved? A. Wash the patient's red cells and repeat the forward grouping B. Test the patient's plasma against A2 cells C. Warm the patient plasma at 37°C for 10 minutes and repeat the reverse grouping D. Treat the A1 cells with dithiothreitol and repeat the reverse grouping
C. Warm the patient plasma at 37°C for 10 minutes and repeat the reverse grouping Anti-P1 is a cold-reacting antibody. Warming the plasma at 37°C will dissipate the antibody, preventing its reactivity with P1 antigen on the A1 cells.
Should an O-negative mother receive RhIg if a positive DAT on the newborn is caused by immune anti-A? A. No, the mother is not a candidate for RhIg because of the positive DAT B. Yes, if the baby's type is Rh negative C. Yes, if the baby's type is Rh positive D. No, the baby's problem is unrelated to Rh blood group antibodies
C. Yes, if the baby's type is Rh positive RhIg is immune anti-D and is given to Rh-negative mothers who give birth to Rh-positive babies and who do not have anti-D already formed from previous pregnancies or transfusion
A Kleihauer-Betke acid elution test identifies 40 fetal cells in 2,000 maternal red cells. How many full doses of RhIg are indicated? A. 1 B. 2 C. 3 D. 4
D. 4 To calculate the number of vials of RhIg to infuse, divide 40 by 2,000 and multiply by 5,000, which is the estimated total blood volume of the mother in milliliters. Divide this number by 30 to arrive at the number of doses. When the number to the right of the decimal point is less than 5, round down and add one dose of RhIg. Conversely, when the number to the right of the decimal point is 5 or greater, round up and add one dose of RhIg. In this example, the number of doses is 3.3. Rounding down and adding 1 vial gives an answer of 4 vials.
All of the following are reasons for a positive DAT on cord blood cells of a newborn except: A. High concentrations of Wharton's jelly on cord cells B. Immune anti-A from an O mother on the cells of an A baby C. Immune anti-D from an Rh negative mother on the cells of an Rh-positive baby D. Immune anti-K from an K-negative mother on the cells of a K-negative baby
D. Immune anti-K from an K-negative mother on the cells of a K-negative baby Immune anti-K from the mother would not coat the baby's red cells if they did not contain the K antigen; therefore, the DAT would be negative.
SITUATION: RhIg is requested on a 28-year-old woman with suspected abortion. When the nurse arrives in the blood bank to pick up the RhIg, she asks the medical laboratory scientist (MLS) if it is a minidose. "e MLS replies that it is a full dose, not a minidose. "e nurse then requests to take 50 mcg from the 300 mcg syringe to satisfy the physician's orders. What course of action should the MLS take? A. Let the nurse take the syringe of RhIg, so that she may withdraw 50 mcg B. Call a supervisor or pathologist C. Instruct the nurse that the blood bank does not stock minidoses of RhIg and manipulating the full dose will compromise the purity of the product D. Instruct the nurse that the blood bank does not stock minidoses of RhIg, and relay this information to the patient's physician
D. Instruct the nurse that the blood bank does not stock minidoses of RhIg, and relay this information to the patient's physician Blood banks operate by strict standard operating procedures. These include which products are supplied from the blood bank. While B may also be a solution, D is the best answer because the patient's physician can communicate with the pathologist once he or she receives this information from the nurse.
SITUATION: An O-negative mother gave birth to a B-positive infant. "e mother had no history of antibodies or transfusion. "is was her first child. "e baby was mildly jaundiced and the DAT weakly positive with polyspecific antisera. What could have caused the positive DAT? A. Anti-D from the mother coating the infant red cells B. An alloantibody, such as anti-K, coating the infant red cells C. Maternal anti-B coating the infant cells D. Maternal anti-A, B coating the infant cells
D. Maternal anti-A, B coating the infant cells Anti-A,B is an IgG antibody and can cross the placenta and attach to infant cells. It is known as a single entity as opposed to separate antibodies. Anti-D would not be the cause because this is the first pregnancy. Anti-K is not the cause because there is no history of alloantibodies or past transfusions.
A cold-reacting antibody is found in the serum of a recently transfused patient and is suspected to be anti-I. "e antibody identification panel shows reactions with all cells at room temperature, including the autocontrol. "e reaction strength varies from 2+ to 4+. What procedure would help to distinguish this antibody from other cold-reacting antibodies? A. Autoadsorption technique B. Neutralization using saliva C. Autocontrol using ZZAP reagent-treated cells D. Reaction with cord cells
D. Reaction with cord cells Because RBCs contain variable amounts of I antigen, reactions with anti-I often vary in agglutination strength. However, because this patient was recently transfused, the variation in reaction strength may be the result of an antibody mixture. Although autoadsorption would remove anti-I, this procedure does not confirm the antibody specificity and can result in removal of other antibodies, as well. Cord cells express primarily i antigen with very little I antigen. Anti-I would react weakly or negatively with cord RBCs. ZZAP removes IgG antibodies from red cells. Because anti-I is IgM, the use of ZZAP would not be of value.
An antibody identification panel reveals the presence of anti-Leb and a possible second specificity. Saliva from which person would best neutralize the Leb antibody? Genes Lewis ABO Secretor a. Le H sese b. Le hh Se c. Le H Se d. lele hh sese
c. Le H Se Lewis antibodies are usually not clinically significant but may interfere with testing for clinically significant antibodies. Lewis antibodies are most easily removed by neutralizing them with soluble Lewis substance. The Lewis antigens are secreted into saliva and plasma and are adsorbed onto the red cells. Leb substance is made by adding an L-fucose to both the terminal and next to last sugar residue on the type 1 precursor chain. This requires the Le, H, and Se genes. Since some examples of anti-Leb react only with group O or A2 RBCs, neutralization is best achieved if the saliva comes from a person who is group O.
