Tests and Principles

Question 1

IN what kind of solution is hemoglobin S insoluble that most other hemoglobins, including A, are? what reduces the released Hgb in the solution, and how does the Hgb escape?

Answer 1

concentrated phosphate solutions; hydrosulfite; a surfactant lyses the RBCs

Question 2

What type of blood sample anticoagulant is used for the sickle solubility test?

Answer 2

EDTA preferred, others can be used: clotted specimens are unacceptable,

Question 3

How long can a blood sample be stored at 2 to 8 C prior to Sickle cell solubility screening?

Answer 3

up to two weeks

Question 4

The phosphate buffer used in the SS screening contains what preservative and how must it be handled for disposal>

Answer 4

sodium azide- flush with lots of water to prevent build up of explosive metal azides

Question 5

What’s in the bottom of the SS screen tube?

Answer 5

sodium hydrosulfite

Question 6

AT what temp should samples and reagents be for the sickle solubility screen? what else should be done before testing?

Answer 6

room temp; mix well

Question 7

How does patient’s hemoglobin level affect sickle solubility testing?

Answer 7

If it is = 8 g/dL, add 100 uL sample

If higher, add only 50 uL sample

Question 8

When Hb S is ________ it forms sickled cells due to elongated tactoids.

Answer 8

deoxyhemoglobin/ deoxygenated?

Question 9

WHat are some blood disorders that can give false positive sickle solubility screens? How to resolve?

Answer 9

Multiple myeloma; cryoglobulinemia; other dysglobulinemias;

wash cells in normal saline then bring to normal volume with normal compatible plasma or serum

Question 10

What type of hemoglobin can cause false positives in the sickle solubility screen and therefore what patients can’t be screened this way?

Answer 10

Hb F; under 6 mos old

Question 11

WHat other types of variant hemoglobins can give a positive sickling rxn?

Answer 11

Hgb C Harlem or Georgetown

Question 12

HOw is a positive sickle cell screen followed up?

Answer 12

hemoglobin electrophoresis

Question 13

What does the ESR measure ?

Answer 13

the erythrocyte sedimentation rate, a nonspecific measure of inflammation

Question 14

what is the ratio of blood to anticoagulant in the manual ESR? what is the anticoagulant? Is EDTA specimen acceptable ?

Answer 14

4 parts blood to 1 part sodium citrate; yes but must dilute with the citrate

Question 15

Are controls for the ESR pos/neg or normal/abnormal?

Answer 15

normal/abnormal

Question 16

How is ESR reported and what are normal ranges?

Answer 16

in mm/hr
males, 0 to 22 mm/hr
femlaes, 0 to 29 mm/hr

Question 17

what is the reportable range of the sed rate?

Answer 17

0 to 150 mm/hr

Question 18

what can cause an indistinct boundary between the red cells and plasma of an ESR?

Answer 18

red cell flocculation– in pt’s with a high sed rate this can make determination of true rate impossible

Question 19

what kind of result may occur if the anticoagulant ration is too high in the ESR?

Answer 19

falsely elevated ESR

Question 20

What is the LAP stain and score, and what does it differentiate?

Answer 20

Leukocyte alkaline phosphatase, scored by grading intensity and granule size in 100 neutrophils; Will be decreased in CML (and PNH) and increased in leukemoid reaction ( and PV, blast crisis, late pregnancy

Question 21

what are peroxidase stains useful in diff’ing?

Answer 21

granulocytic cells contain peroxidase in their granules, and to a lesser extent monocytic cells do; however LYMPHOCYTIC series are NEGATIVE
Diffs AML from ALL blasts

Question 22

What does the Schilling test evaluate?

Answer 22

IF deficiency or malabsorption of B12

Question 23

If a patient has an abnormal part I Schilling test but a normal part II, what does this indicate and why?

Answer 23

the patient does not make IF which is the cause of the malabsorption, bc in part II If is added.
If part II is still abnormal there is another cause of malabsorption

Question 24

what tests would be on an appropriate panel for a patient who has had several DVTs and is possibly in a hypercoagulative state?

Answer 24

Pt and aPTT for the baseline (see if there’s an inhibitor); Lupus anticoagulant test (a common cause of thrombosis); activated Protein C Resistance (APC) test; and d-dimer to ensure there is actually thrombosis occurring.

Question 25

in what timeframe should a mixing study be done on a sample, then how stored if not performed?

Answer 25

4 hours; -70 up to 1 year

Question 26

what hemoglobin migrates with S on cellulose, alkaline hemoglobin electrophoresis?

Answer 26

D and G

Question 27

what is the order of migration of hemoglobins on cellulose alkaline electrophoresis from the application point? What migrates along with A2 and may need citrate acid agar ?

Answer 27

A2, C, E first ; S, D, G; F; A

Since C migrates with A2 you would need to clarify with citrate