Intermethod discordance for alpha-fetoprotein measurements in Fanconi anemia.
BACKGROUND
The significantly higher serum alpha-fetoprotein (AFP) in patients with Fanconi anemia (FA) than in non-FA aplastic patients has potential diagnostic utility, but the increase is method-dependent. The aim of this study was to compare five AFP assays on FA and non-FA samples and to investigate possible explanations for FA-specific discrepancies.


METHODS
Two methods available in our laboratory (Kryptor and IMx) were compared on 59 FA and 27 non-FA patient samples. Kryptor, Immulite, Elecsys, Immuno-I, and Elsa-2 methods were then compared on 14 FA and 14 non-FA patient samples. The AFP glycosylation profile was analyzed by electrophoretic separation in a lectin-containing gel.


RESULTS
With all six methods, AFP values were significantly higher in FA than in non-FA patients, but the diagnostic precision and optimal cutoff values varied. Indeed, two methods reached 100% sensitivity and specificity, but in other methods, one or both of these parameters were significantly <100%. Neither heterophilic antibodies nor a specific glycosylation profile was detected in FA samples.


CONCLUSIONS
AFP results are method-dependent in FA. New methods must be evaluated before use in differential diagnosis of aplastic patients.
Cassinat
B
B
Nuclear Medicine Department, Assistance Publique-Hôpitaux de Paris, Saint-Louis Hospital, 75010 Paris, France. cassinat@chu-stlouis.fr
Darsin
D
D
Guardiola
P
P
Toubert
M E
ME
Rain
J D
JD
Gluckman
E
E
Schlageter
M H
MH
D000293:Adolescent; D000328:Adult; D000741:Anemia, Aplastic / Q000097:blood / Q000175:diagnosis; D000910:Antibodies, Heterophile / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004587:Electrophoresis, Agar Gel; D005199:Fanconi Anemia / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007223:Infant; D037102:Lectins; D008297:Male; D008875:Middle Aged; D020033:Protein Isoforms / Q000097:blood; D011786:Quality Control; D000509:alpha-Fetoproteins / Q000032:analysis*
D000910:Antibodies, Heterophile; D037102:Lectins; D020033:Protein Isoforms; D000509:alpha-Fetoproteins