Schoenfeld N, Sztern M, Mamet R
Porphyria Reference Laboratory, Rabin Medical Center, Petah Tiqva, Israel.
Cell Mol Biol (Noisy-le-grand). 1997 Feb;43(1):81-8.
A distressingly common occurrence is the erroneous diagnosis of hepatic porphyria in patients with chronic abdominal pain in which either urinary porphyrins are elevated and/or Watson-Schwarz test is positive. This work investigates a characteristic case and points at possible pitfalls in establishing a diagnosis. In the patient described, spot urine analysis showed positive Watson-Schwarz test and increased porphyrins at three separate occasions, while normal values of precursors and porphyrins were recorded in 24-hrs. urinary collections during four hospitalization periods for acute abdominal pain. Various colorimetric and HPLC methods employed excluded the diagnosis of porphyria and led to resolving the discrepancy between home and hospital results. It was found that the false increase in porphyrins in the spot samples emerged from a substance present in yeast tablets which the patient was consuming. The positive Watson-Schwarz test obtained was probably the result of the fact that the urine samples were concentrated with creatinine values exceeding 400 mg%. The case reported above, as well as studies carried out in three healthy volunteers and in an AIP patient, led to the conclusion that in order to obtain reliable result, 24-hrs. urinary collections should be examined, rather than spot urine samples.
在患有慢性腹痛的患者中，错误诊断为肝卟啉症的情况令人苦恼地普遍存在，这些患者的尿卟啉升高和/或沃森-施瓦茨试验呈阳性。这项工作研究了一个典型病例，并指出了诊断过程中可能存在的陷阱。在所描述的患者中，随机尿分析显示沃森-施瓦茨试验呈阳性，且在三个不同时间点卟啉增加，而在四次因急性腹痛住院期间的24小时尿液收集记录中，前体和卟啉值均正常。采用的各种比色法和高效液相色谱法排除了卟啉症的诊断，并解决了在家检测结果与医院检测结果之间的差异。发现随机样本中卟啉的假性增加源自患者正在服用的酵母片中存在的一种物质。获得的阳性沃森-施瓦茨试验结果可能是由于尿样中肌酐值超过400mg%而浓缩所致。上述病例以及在三名健康志愿者和一名急性间歇性卟啉症患者身上进行的研究得出结论，为了获得可靠结果，应检测24小时尿液收集样本，而不是随机尿样。
